Amine tungstates and lubricant compositions

ABSTRACT

This invention relates to lubricating oil additives, and to lubricating oil compositions, their method of preparation, and use. More specifically, this invention relates to several novel lubricating oil additives and compositions which contain a tungsten compound and an antioxidant, namely aminic antioxidants such as a secondary diarylamine or an alkylated phenothiazine. The use of the tungsten compound with the secondary diarylamine and/or the alkylated phenothiazine provides improved oxidation and deposit control to lubricating oil compositions. The lubricating oil compositions of this invention are particularly useful as crankcase and transmission lubricants, gear oils and other high performance lubricant applications.

This application is a continuation-in-part of U.S. patent application Ser. No. 11/457,144, filed on Jul. 12, 2006, which claims the benefit of priority to U.S. Provisional Application 60/698,750, filed on Jul. 12, 2005. The contents of both U.S. patent application Ser. No. 11/457,144 and U.S. Provisional Application 60/698,750 are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to lubricating oil additives, and to lubricating oil compositions, their method of preparation, and use. More specifically, this invention relates to several novel lubricating oil additives and compositions which contain a tungsten compound and an antioxidant, namely aminic antioxidants such as a secondary diarylamine or an alkylated phenothiazine. The use of the tungsten compound with the secondary diarylamine and/or the alkylated phenothiazine provides improved oxidation and deposit control to lubricating oil compositions. The lubricating oil compositions of this invention are particularly useful as crankcase and transmission lubricants, gear oils and other high performance lubricant applications.

BACKGROUND OF THE INVENTION

Lubricating oils as used in, for example, the internal combustion engines of automobiles or trucks are subjected to a demanding environment during use. This environment results in the oxidation of the oil catalyzed by the presence of impurities in the oil, such as iron compounds, and is also promoted by the elevated temperatures experienced by the oil during use. This catalyzed oxidation of the oil not only contributes to the formation of corrosive oxidation products and sludge in the oil but can also cause the viscosity of the oil to increase or even cause the oil to solidify. This oxidation of lubricating oils during use is usually controlled to some extent by the use of antioxidant additives which may extend the useful life of the oil, for example, by reducing or preventing unacceptable viscosity increases.

Aminic antioxidants are antioxidants that contain one or more nitrogen atoms, such as alkylated diphenyl amines and phenothiazines. Phenolic antioxidants contain one or more sterically hindered phenol functionalities, and can be either used alone or in synergistic combinations with alkylated aminic antioxidants. The synthesis and uses of phenolic antioxidants, phenothiazines and aromatic amines have been reported. Phenothiazine antioxidants have been used as a stand alone additive, chemically modified or grafted onto the backbone of polymers.

There is, however, a continuing need for new antioxidants and antioxidant systems which offer improved performance and which are effective at low levels. There are a number of factors which have contributed to this continuing need. One such factor is that in recent years internal combustion engines are often operated at even higher temperatures, which tend to increase the rate of oxidation and shorten the useful life of the oil. In addition, there is a strong desire to use cheaper base stocks for lubricating oil compositions which have inferior resistance to oxidation and require more efficient and effective antioxidants. There is also a need for lubricating oils to have a longer in service life span to support the longer service intervals for motor vehicles. There is also a desire to find antioxidants and antioxidant systems which meet the above requirements and at the same time are not detrimental to other aspects of motor vehicle performance. In this respect there is a desire for antioxidants which do not contribute to the phosphorus content of motor vehicle exhausts, as phosphorus is detrimental to the performance of catalyst based exhaust purification systems. The trend to reduce phosphorus levels in the final formulation has led to use of lower levels of zinc dialkyldithiophosphates, (ZDDP). This has led to an overall reduction in the levels of antioxidants used in the final formulation because ZDDP also serves as an antioxidant, in addition to an extreme-pressure/antiwear additive. The trend to reduce the total levels of sulfur in lubricants will also lead to lower use levels of sulfur containing multifunctional antioxidant extreme-pressure additives such as sulfurized olefins, and other sulfur containing detergents. In addition some antioxidants, such as for example diphenylamines, cannot be used at relatively high concentrations as this may result in sedimentation or deposits in hot engine areas such as the diesel ring areas in diesel engines. The invention is concerned with the problem of providing an improved antioxidant for use in lubricating oils.

SUMMARY OF THE INVENTION

This invention relates to new tungsten containing lubricating oil additives, compositions, their method of preparation, and use. More specifically, this invention relates to lubricating oil compositions which contain a tungsten compound and an aminic antioxidant such as alkylated diphenyl amines and/or alkylated phenothiazines. In addition the composition may additionally include a sulfur-containing additive such as sulfurized olefins, sulfurized vegetable oils, sulfurized animal fats and oils, sulfurized fatty acids, sulfurized synthetic esters, sulfurized acrylates and sulfurized methacrylates, and sulfurized succinic acid derivatives, thiadiazole, dithiocarbamate, dithiophosphate and mixtures thereof. The use of both the tungsten containing additive and the alkylated secondary diarylamine, and alternatively further with phenothiazine, provides improved oxidation and deposit control to lubricating oil compositions. The lubricating oil compositions of this invention are particularly useful as crankcase and transmission lubricants, gear oils and other high performance lubricant applications.

The antioxidant additive compositions of this invention result in low levels of deposits and display improved corrosion inhibition and friction properties.

This invention provides compositions comprising certain tungsten containing compounds and antioxidants, namely certain aromatic amines, either alone or in combination with phenolic antioxidants, that provide a highly effective regenerative antioxidant system for use in lubricating oils, especially in lubricating oils for gasoline and diesel engines. Lubricating oils as used in the internal combustion engines and transmissions of automobiles or trucks, gear oils and other high temperature lubricant applications are subjected to a demanding environment during use. This environment results in the oxidation of oil which is catalyzed by the presence of impurities in the oil (such as iron compounds) and promoted by the elevated temperatures of the oil during use.

This invention also provides lubricating oil compositions with enhanced performance properties that result from suprising synergistic interactions between the amine tungstates and various lubricant additives, such as ashless friction modifiers, metal-containing antiwear additives, ashless antiwear additives, extreme pressure agents, corrosion inhibitors/detergents, yellow metal deactivators/copper passivating agents, or mixtures thereof.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides compositions containing various amine tungstate compounds and various amine additives which display synergistically enhanced friction reducing properties compared to previously reported amine tungstate-based compositions that include sulfur or phosphorus compounds and additional metallic additives.

It has been found that the combination of (1) an oil soluble or dispersible tungsten compound and (2) a secondary diarylamine, such as an alkylated diphenylamine, either alone or in combination with also preferably an alkylated, phenothiazine, is highly effective at controlling crankcase lubricant oxidation and deposit formation. Examples of the types of compounds that may be used in this invention are described in the following. The tungsten compound may be used between 20 and 4000 ppm, preferably between 20 to 1000 ppm, based on the amount of tungsten delivered to the finished lubricating oil. Alkylated phenothiazines, secondary diarylamines, and other suitable aminic antioxidants may be used at concentrations ranging from 0.05 to 2.5 wt. % in the finished lubricant, preferably between 0.1 to 1.0 wt. %. In some embodiments of the invention, an oil soluble or dispersible molybdenum compound may be substituted for the tungsten compound. In addition to the antioxidants of this invention, the lubricating composition may also contain dispersants, detergents, anti-wear additives including for example ZDDP, ashless dithiophosphates, ashless phosphorothioates and thiophosphates, ashless dithiocarbamates, additional antioxidants if required, friction modifiers, corrosion inhibitors, anti-foaming additives, pour point depressants and viscosity index improvers. The lubricant may be prepared from any paraffinic, naphthenic, aromatic, or synthetic base oil, or mixtures thereof. In an embodiment, the lubricant may contain between 250 and 1000 ppm of phosphorus derived from ZDDP and between 500 and 3000 ppm of calcium from calcium containing sulfonate detergents or calcium containing phenate detergents. In this manner, both crankcase and automatic transmission fluid (ATF) lubricants, gear oils and other high temperature lubricants are readily prepared.

Thus, one embodiment of the present invention provides crankcase and transmission fluid lubricants, gear oils and other high temperature industrial lubricants and additive package concentrates, which contain very low levels of phosphorus. More preferred are lubricant compositions containing zero or essentially zero phosphorus. By “essentially zero phosphorus” herein is meant phosphorus levels of less than or equal to about 100 ppm.

In another embodiment, the lubricant does not contain ZDDP, but may contain other sources of phosphorus, including ashless dithiophosphates,

I. Tungsten Compounds of the Current Invention and their Preparation

1.0 Sulfur- and Phosphorus-Free or Organotungsten Compounds

Sulfur- and phosphorus-free organotungsten compounds that are a component of the present invention may be prepared by reacting a sulfur and phosphorus-free tungsten source with an organic compound containing an amino group. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium para tungstate, ammonium meta tungstate, sodium tungstate and potassium tungstate. The amino groups may be monoamines, diamines, or polyamines, containing primary, secondary or tertiary amine functionalities. The primary amine structure may be

which R¹, R² and R³ are independently hydrogen, C₁-C₂₅ alkyl, C₂-C₂₅ alkyl interrupted by oxygen or sulfur; C₂-C₂₄ alkenyl, C₄-C₁₅ cycloalkyl which is unsubstituted or substituted by C₁-C₄ allyl and/or carboxyl; C₅-C₁₅ cycloalkenyl which is unsubstituted or substituted by C₁-C₄ alkyl and/or carboxyl; C₁₃-C₂₆ polycycloalkyl, C₇-C₉ phenylalkyl which is unsubstituted or substituted on the phenyl ring by C₁-C₄ alkyl; —COR₆, a 5- or 6-membered heterocyclic ring which is unsubstituted or substituted by C₁-C₄ alkyl, C₁-C₄ alkoxy, halogen or carboxyl; a 5- or 6-membered heterocyclic ring which is benzo-fused and is unsubstituted or substituted by C₁-C₄ alkyl, C₁-C₄ alkoxy, halogen or carboxyl.

For example, the secondary amine is of the following structure

wherein R⁴ and R⁵ are independently hydrogen, linear, branched, saturated or unsaturated alkyl of 1 to 40 carbon atoms, cycloalkyl of 5 to 40 carbon atoms, aryl of 6 to 40 carbon atoms, aralkyl of 7 to 9 carbon atoms, where the aralkyl may be substituted by alkyl of 1 to 36 carbon atoms.

The tertiary amine is preferably represented by general formula

wherein R₁, R₂, and R₃ are independently each a C₁ to C₃₆ residue that may optionally contain at least one —O—, —S—, —SO—, —CO₂—, —CO—, or —CON— moiety, cycloalkyl of 5 to 12 carbon atoms, aralkyl of 7 to 9 carbon atoms, where the aralkyl may be substituted by alkyl of 1 to 36 carbon atoms.

Specific examples of the amine tungstates are those derived from Primene JM-T, tert-octadecylamine, tert-eicosylamine, 1-methyl-1-ethyl octadecyl amine, 1,1-dimethyl octadecylamine, 1-methyl-1-butyl hexadecylamine, 1-triacontylamine, oleyl amine, lauryl amine, and tall oil amine.

Polyamines are preferably represented by general formula

wherein R₇, R₈ and R₉ are each independently hydrogen; C₁ to C₂₅ straight or branched chain alkyl radicals; C₁ to C₁₂ alkoxy-(C₆ alkylene) radicals; C₂ to C₁₂ alkylamino-C₂ to C₆ alkylene) radicals; each s can be the same or a different number of from 1 to 6, preferably 2 to 4; and t is a number from 0 to 10, preferably 2 to 7. At least one of R₇, R₈ and R₉ must be hydrogen.

Suitable amines include: 1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethylene amines such as diethylene triamine; triethylene tetramine; tetraethylene pentamine; polypropylene amines such as 1,2-propylene diamine; di-(1,2-propylene)triamine; di(1,3-propylene)-triamine; N,N-dimethyl-1,3-diaminopropane; N,N-di-(2-aminoethyl) ethylene diamine; N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propane diamine; tris hydroxymethylaminomethane (THAM); diisopropanol amine; diethanol amine; triethanol amine; amino morpholines such as N-(3-amino-propyl) morpholine; etc.

In order to improve solubility of the organotungsten product in base oils and finished oils, it is useful for the mono-substituted diamine to have a high hydrocarbon character. For example, the diamine can be represented by the following general structure:

where x is 1 or 2, and R is a hydrocarbon-containing group containing a minimum of about 6 carbon atoms, and up to 24 carbon atoms. R can be aliphatic or aromatic. R, in addition to the minimum of about 6 carbon atoms, may also contain oxygen, but preferably R does not include sulfur or additional nitrogen. It is preferred that R contains a minimum of 10 carbon atoms in order to further improve the organotungsten product solubility in base oil. The most preferred R contains oxygen in addition to the carbons, such as where R is an alkyloxyalkylene group. Where R represents an alkyloxyalkylene group, R can be represented by the structure —X₁—O—X₂, where X₁ is an alkylene of 2, 3 or 4 carbons and preferably is propylene or ethylene, and X₂ is an alkyl moiety having 3 to 30 carbon atoms, more preferably an alkyl moiety having 7 to 20 carbon atoms, and where X₂ can be a straight or branched, saturated or partially unsaturated hydrocarbon chain.

Examples of some mono-substituted diamines that may be used include phenylaminopropylamine, hexylaminopropylamine, benzylaminopropylamine, octylaminopropylamine, octylaminoethylamine, dodecylaminopropylamine, dodecylaminoethylamine, hexadecylaminopropylamine, hexadecylaminoethylamine, octadecylaminopropylamine, octadecylaminoethylamine, isopropyloxypropyl-1,3-diaminopropane, octyloxypropyl-1,3-diaminopropane, decyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, dodecyloxypropyl-1,3-diaminopropane, tetradecyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, isododecyloxypropyl-1,3-diaminopropane, isotridecyloxypropyl-1,3-di a-minopropane. Mono-substituted diamines derived from fatty acids may also be used. Examples include N-coco alkyl-1,3-propanediamine (Duomeen C), N-tallow alkyl-1,3-propanediamine (Duomeen T), and N-oleyl-1,3-propanediamine (Duomeen OL), all obtained from Akzo Nobel.

Other useful amine compounds include alicyclic diamines such as 1,4-di-(aminomethyl) cyclohexane, and heterocyclic nitrogen compounds such as imidazolines, and N-aminoalkyl piperazines of the general formula:

wherein p₁ and p₂ are the same or different and each is an integer from 1 to 4, and e, f and o are the same or different and each is an integer from 1 to 3.

in which n=2 or 3, m=1 or 2, R^(a), R^(b) and R^(c) are identical or different, and represent hydrogen, alkyl, or substituted alkyl, hydroxyalkyl, aryl, aralkyl, cycloalkyl, heterocyclics, ether, thioether, halogen, —N(R)₂, polyethylene polyamines, nitro groups, keto groups, ester groups, or carbonamide groups, alkyl substituted with the various functional groups described above, and T represents alkyl, alkylene, aryl, aralkyl, cycloalkyl or heterocyclic radical, substituted if desired with halogen, nitro groups, alkyl groups, alkoxy groups or amino groups, and, when m=1, T represents hydrogen. Salts of the above structures include carboxylic including aliphatic, aromatic and poly carboxylic, carbonic, sulfonic and phosphoric acid salts.

R^(a), R^(b), R^(c) are independently hydrogen, alkyl, alkenyl, or alkoxy of 1 to 36 carbons, cycloalkyl of 6 to 32 carbons, alkylamino of 1 to 36 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenyl, hydroxyalkyl, or hydroxycycloalkyl of 1 to 20 carbon atoms, methoxyalkyl of 1 to 20 carbon atoms, aralkyl of 7 to 9 carbon atoms, where the aryl group of the aralkyl is further substituted by alkyl of 1 to 36 carbon atoms. When m=2, T is alkylene of 1 to 12 carbons or arylene of 6 to 10 carbons, or a plurality of radicals being able to be joined, containing hetero atoms also by hetero atoms such as O, N or S, if desired.

Preferred imidazoline structures are where R is a long chain alkyl up to 18 carbon atoms, m=1 and R^(c) is one of 2-hydroxyethyl, or 2-aminoethyl or 2-amido ethyl substituents.

Examples of such amines include 2-pentadecyl imidazoline, aminoethyl oleyl imidazoline and N-(2-aminoethyl) piperazine.

2.0 Sulfur-Containing Organotungsten Compounds

The sulfur-containing organotungsten compounds of the invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an amino group and one or more sulfur sources. Non-limiting examples of sulfur sources include carbon disulfide, hydrogen sulfide, sodium sulfide and elemental sulfur. Alternatively, the sulfur-containing tungsten compounds may be prepared by the reaction of a sulfur-free tungsten source with an amino group or thiuram group and optionally a second sulfur source. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate, potassium tungstate and tungsten halides. The amino groups may be monoamines, diamines, or polyamines. As an example, the reaction of tungsten trioxide with a secondary amine and carbon disulfide produces tungsten dithiocarbamates.

An alternate approach includes the reaction of sulfur- and phosphorus-free tungsten sources including tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate, and potassium tungstate with a sulfurated amine precursor.

Examples of sulfur containing organotungsten compounds appearing in patents and patent applications include the following all of which are hereby incorporation by reference in their entirety:

Compounds prepared by the reaction of divalent metal tungstates with dithiocarbamates in an alkaline sodium sulfide and/or sodium hydrogen sulfide solution as described in WO 2004/043910 A2.

Compounds prepared by the reaction of a primary amine with a CS₂ or COS, and subsequent reaction of the dithiocarbamic acid produced with a tungsten containing compound, as described in U.S. Pat. No. 4,846,983.

Sulfurized oxymetalorganophosphorodithioates, and sulfurized oxymetal dithiocarbamates as described in U.S. Pat. No. 4,529,526 wherein the metal is tungsten.

Tungsten dithiocarbamates are illustrated with the following structure,

where R⁶ and R⁷ are independently the same or different and are selected from H and C₁ to C₃₀ and are an alkyl group, a cycloalkyl group, an aryl group or an alkaryl group, with the proviso that at least one of R⁶ or R⁷ is H for at least one of the thiocarbamate groups, and at least one of R⁶ or R⁷ is hydrocarbyl for each of the thiocarbamate groups, M is W, X is O or S, b₁ is at least 1, a₁ is at least 1 depending on the oxidation state of M, c₁ is at least 1 depending on the oxidation state of M and d₁ is 0 or at least 1 depending on the oxidation state of M. Generally, a₁ and b₁ will range from 1 to about 5, c₁ will range from 1 to about 6 and d₁ will be 0 or range from 2 to about 10. In a preferred embodiment, a₁ will be 1 or 2, b₁ will be 1 or 2, c₁ will be 1 or 2, and d₁ will be 0 or 2.

Sulfurized oxymetal organophosphorodithioates are illustrated with the following structure.

wherein M is tungsten, R⁸ and R⁹ may be the same or different, each of R⁸ and R⁹ contains from 1 to 30 carbon atoms and are selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group, and a alkylaryl group; and x₁ and y₁ are positive real numbers satisfying the equation: x₁+y₁=4.

3. Silicon Containing Organotungsten Compounds

The silicon containing organotungsten compound of this invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an amino silane. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

Particularly useful are aminosilanes of the formula

in which R₁₇ and R₁₈ are independently hydrogen, C₁-C₂₅ alkyl, 2-hydroxyethyl, C₃-C₂₅ alkyl which is interrupted by oxygen or sulfur; C₂-C₂₄ alkenyl or

R₁₉ is C₁-C₂₅ alkyl, C₂-C₂₅ alkyl which is interrupted by oxygen or sulfur; hydroxyl, C₁-C₁₈ alkoxy or C₂-C₂₄ alkenyl, R₂₀ is hydroxyl, C₁-C₁₈ alkoxy or C₂-C₁₈ alkoxy which is interrupted by oxygen or sulfur; and, if a and b together are 1, three radicals R₂₀ together are N(CH₂CH₂O—)₃, X₃ is C₁-C₁₈ alkylene, C₂-C₂₀ alkylidene, C₇-C₂₀ phenylalkylidene, C₅-C₈ cycloalkylene, phenylene or naphthylene which is unsubstituted or substituted by C₁-C₄ alkyl; or is C₄-C₁₈ alkylene which is interrupted by oxygen, sulfur or

R₂₁ is hydrogen or C₁-C₈ alkyl with the proviso that two nitrogen atoms are not attached to the same carbon atom, a is 1 or 2, and b is 0, 1 or 2.

Examples of amino silanes useful in this invention include, aminopropyl triethoxysilane, aminopropyl trimethoxy silane, aminopropyl diethoxysilane, aminopropyl methyldimethoxysilane, aminoethyl aminopropyltrimethoxysilane, aminoethyl aminopropylmethyldimethoxysilane, aminoethyl aminopropylmethyldiethoxysilane, aminoethyl aminomethyltriethoxysilane, aminoethyl aminomethylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, diethylenetriaminopropylmethyldimethoxysilane, diethylenetriaminopropylmethyldiethoxysilane, diethylenetriaminomethyldimethoxysilane, cyclohexylaminopropyltrimethoxysilane, cyclohexylaminopropyltriethoxysilane, cyclohexylaminopropylmethyldimethoxysilane, cyclohexylaminopropylmethyldiethoxysilane, cyclohexylaminomethyltriethoxysilane, cyclohexylaminomethylmethyldiethoxysilane, hexanediaminomethyltriethoxysilane, phenylaminomethyltrimethoxysilane, phenylaminopropyltrimethoxysilane, phenylaminopropyltriethoxysilane, phenylaminopropyl methyldimethoxysilane, phenylaminopropyl methyldiethoxysilane, phenylaminomethylmethyldimethoxysilane, phenylaminomethylmethyldiethoxysilane, phenylaminomethyltriethoxysilane, diethylaminomethyltriethoxysilane, diethylaminomethyltrimethoxysilane, diethylaminopropyltrimethoxysilane, diethylaminopropyl methyldimethoxysilane, diethylaminopropyl methyldiethoxysilane, dimethylaminopropyl methyldiethoxysilane, (diethylaminomethyl)methyldiethoxysilane, methylaminopropyltrimethoxysilane, bis((3-triethoxysilyl)propyl) amine, piperazinylpropylmethyldimethoxysilane, piperazinylpropylmethyldiethoxysilane, piperazinylmethylmethyldiethoxysilane, morpholinylpropyltrimethoxysilane, morpholinylpropyltriethoxysilane, morpholinylpropylmethyldimethoxysilane, morpholinylpropylmethyldiethoxysilane, morpholinylmethyltriethoxysilane, morpholinylmethylmethyldiethoxysilane, diaminomethylmethyldiethoxysilane, dimethyldiaminopropylmethyldiethoxysilane, dimethyldiaminomethylmethyldiethoxysilane, aminohexylaminomethyltrimethoxysilane, aminohexylaminopropyltrimethoxysilane, octanoylaminopropyltriethoxysilane, methylaminopropyltrimethoxysilane, methylaminopropylmethyldiethoxysilane, methylaminomethylmethyldiethoxysilane, ethylaminopropylmethyldiethoxysilane, ethylaminomethylmethyldiethoxysilane.

Also useful are silicone amines commercially available from Siltech under the Silamine tradename. The structures mentioned in the U.S. Pat. No. 5,378,787, which is hereby incorporation by reference in its entirety, are also useful and are as follows:

where a and b are integers ranging from 0 to 2000.

4.0 Organoamine Tungstates with Ethoxylated Amines

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an ethoxylated amine. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

Particularly useful ethoxylated fatty amines are

where Z is straight or branched chain alkyl of from about 8 to 26 carbon atoms, alkoxy alkyl of 4 to 22 carbon atoms, n=2 to about 50, and x₁=from about 1 to about 49.

Specific embodiments include, isopropyloxypropyl amine, isohexyloxypropyl amine, 2-ethylhexyloxypropyl amine, octyl/decyloxy propyl amine, isodecyloxypropyl amine, isododecyloxypropyl amine, dodecyl/tetradecyloxypropyl amine, isotridecyloxypropyl amine, tetradecyloxypropyl amine, linear alkoxypropyl amine, octadecyl/hexadecyloxypropyl amine, octyl/decyloxy propyl-1,3-diaminopropane, isodecyloxypropyl 1,3-diaminopropane, isododecyloxypropyl 1,3-diaminopropane, dodecyl/tetradecyloxypropyl 1,3-diaminopropane, isotridecyloxypropyl 1,3-diaminopropane, tetradecyloxypropyl 1,3-diaminopropane, bis-(2-hydroxyethyl) isodecyloxypropyl amine, bis-(2-hydroxyethyl) isotridecyloxypropyl amine, bis-(2-hydroxyethyl) linear alkoxypropyl amine, bis-(2-hydroxyethyl) soya amine, bis-(2-hydroxyethyl) tallow amine, poly (5) oxyethylene isodecyloxypropyl amine, poly (5) oxyethylene isotridecyloxypropyl amine, N-tallow-poly (3) oxyethlene-1,3-diaminopropane, isodecyloxypropyl bis-(2-hydroxyethyl)methyl ammonium chloride, isotridecyloxypropyl bis-(2-hydroxyethyl)methyl ammonium chloride, octadecyl bis-(2-hydroxyethyl)methyl ammonium chloride, isotridecyloxypropyl poly (5) oxyethylene methyl ammonium chloride, monosoya methyl ammonium chloride, tallow diamine diquaternary coco poly (15) oxyethylene methyl ammonium chloride and trimethyl stearyl ammonium chloride.

5. Organoamine Tungstates with Alkylated Phenothiazine

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an alkylated phenothiazine. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

An alkylated phenothiazine suitable for this invention must be oil soluble or dispersible and correspond to the general formula below where the substituents R₁₁-R₁₄ could contain heteroatoms,

R₁₁ and R₁₂ are hydrogen or together can form a fused six-member aromatic ring.

One of R₁₃ and R₁₄ is hydrogen and the other is C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl, —C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl; or both R₁₃ and R₁₄ are C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl-C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl, if R₁₁ and R₁₂ hydrogen; or R₁₃ is hydrogen and R₁₄ is C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl-C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl, if R₁₁ and R₁₂ together form a fused six-member aromatic ring.

R₁₅ is hydrogen, C₁-C₁₂ alkyl, benzyl, allyl, methallyl, phenyl or a group —CH₂SR₄, where R₄ is C₄-C₁₈ alkyl, —CH₂CH₂COO(C₄-C₁₈ alkyl), or an alkylene, aralkylene bridging two phenothiazine moieties.

Typical examples of alkylphenothiazine include but are not limited to monotetradecylphenothiazine, ditetradecylphenothiazine, monodecylphenothiazine, didecylphenothiazine monononylphenothiazine, dinonylphenothiazine, monoctylphenothiazine and dioctylphenothiazine.

6. Organoamine Tungstates with Alkylated Diarylamine

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an alkylated diarylamine. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

The diarylamines that may optionally be used and that have been found to be useful in this invention are well known antioxidants and there is no known restriction on the type of diarylamine that can be used. Preferably, the diarylamine has the formula:

Wherein R₂₂ and R₂₃ each independently represents a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms. Illustrative of substituents for the aryl group include aliphatic hydrocarbon groups such as alkyls having from 1 to 30 carbon atoms, hydroxy groups, halogen radicals, carboxylic acid or ester groups, or nitro groups. The aryl is preferably substituted or unsubstituted phenyl or naphthyl, particularly wherein one or both of the aryl groups are substituted with at least one alkyl having from 4 to 30 carbon atoms, preferably from 4 to 18 carbon atoms, most preferably from 4 to 12 carbon atoms. It is preferred that one or both aryl groups be substituted, e.g. mono-alkylated diphenylamine, di-alkylated diphenylamine, or mixtures of mono- and di-alkylated diphenylamines.

R₂₄ is hydrogen, C₁-C₁₂ alkyl, benzyl, allyl, methallyl, phenyl or a group —CH₂SR₅, where R₅ is C₄-C₁₈ alkyl, —CH₂CH₂COO(C₄-C₁₈ alkyl), or an alkylene, aralkylene bridging two amine moieties.

The diarylamines used in this invention can be of a structure other than that shown in the above formula that shows but one nitrogen atom in the molecule. Thus the diarylamine can be of a different structure provided that at least one nitrogen has 2 aryl groups attached thereto, e.g. as in the case of various diamines having a secondary nitrogen atom as well as two aryl groups bonded to one of the nitrogen atoms.

The diarylamines used in this invention should be soluble in the formulated crankcase oil package. Examples of some diarylamines that may be used in this invention include diphenylamine; alkylated diphenylamines; 3-hydroxydiphenylamine; N-phenyl-1,2-phenylenediamine; N-phenyl-1,4-phenylenediamine; monobutyldiphenylamine; dibutyldiphenylamine; monooctyldiphenylamine; dioctyldiphenylamine; monononyldiphenylamine; dinonyldiphenylamine; monotetradecyldiphenylamine; ditetradecyldiphenylamine; phenyl-alpha-naphthylamine; monooctyl phenyl-alpha-naphthylamine; phenyl-beta-naphthylamine; monoheptyldiphenylamine; diheptyldiphenylamine; p-oriented styrenated diphenylamine; mixed butyloctyldiphenylamine; and mixed octylstryryldiphenylamine, and mixtures thereof. Examples of commercial diarylamines include, for example, IRGANOX™ L06, IRGANOX™ L57 (mixed butyloctyl diphenyl amine) and I IRGANOX™ L67 from Ciba Specialty Chemicals; NAUGALUBE™ AMS, NAUGALUBE™ 438, NAUGALUBE™ 438R, NAUGALUBE™ 438L, NAUGALUBE™ 500, NAUGALUBE™ 640, NAUGALUBE™ 680, and NAUGARD PANA™ from Crompton Corporation; GOODRITE™ 3123, GOODRITE™ 3190X36, GOODRITE™ 3127, GOODRITE™ 3128, GOODRITE™ 3185X1, GOODRITE™ 3190×29, GOODRITE™ 3190×40, GOODRITE™ 3191 and GOODRITE™ 3192 from Noveon Specialty Chemicals; VANLUBE™ DND, VANLUBE™ NA, VANLUBE™ PNA, VANLUBE™ SL (mixed octylstyryl diphenylamine), VANLUBE™ SLHP, VANLUBE™ SS, VANLUBE™ 81, VANLUBE™ 848, and VANLUBE™ 849, VANLUBE™ 961 (mixed butyloctyl diphenyl amine) from R. T. Vanderbilt Company Inc, LUBRIZOL™ 5150A & C from LUBRIZOL™, and NA-LUBE™ AO-140 (mixed butyloctyl diphenyl amine), NA-LUBE™ AO-150 (mixed octylstyryl diphenylamine), from King Industries.

7. Organoamine Tungstates with Amines Containing Other Stabilizing Moieties

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an alkylated triazole, or a phenolic antioxidant. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

A triazole having the formula

wherein R₂₅ is hydrogen or a C₁-C₂₀ alkyl residue; R₂₆ and R₂₇ are the same or different and each is H, C₁-C₂₀ alkyl, C₃-C₂₀ alkenyl, C₅-C₁₂ cycloalkyl, C₇-C₁₃ aralkyl, C₆-C₁₀ aryl or R₂₆ and R₂₇, together with the nitrogen atom to which they are attached, form a 5-, 6- or 7-membered heterocyclic residue or R₂₆ and R₂₇ is each a residue of formula:

R₂₈X₃[(alkylene)O]n₁(alkylene)-

wherein X₃ is O, S or N(R₂₈), R₂₈ is hydrogen or C₁-C₂₀ alkyl, “alkylene” is a C₁-C₁₂ alkylene residue and n₁ is an integer from 0 to 6;

R₃₀ is hydrogen, C₁-C₂₀ alkyl or C₆-C₁₀ aryl or C₇-C₁₈ alkyl phenyl; and R₃₁ is hydrogen, C₁-C₂₀ alkyl or a residue —CH₂NR₂₆R₂₇ wherein R₂₆ and R₂₇ have their previous significance or

R₂₆ has its previous significance and R₂₇ is a residue of formula

or R₂₇ is a residue of formula as defined above and R₂₆ is a residue of formula

-[alkylene]n₁-N(R₃₂)-A-[N(R₃₂)₂]m₁)

in which m₁ is 0 or 1, and when m₁ is 0, A is a residue of formula (I,) and when m₁ is 1, A is alkylene or C₆-C₁₀ arylene, and alkylene and n₁ have their previous significance and R₃₂ is a residue of formula I, as defined above.

A substituted phenol of the formula

wherein, R₄₂, are independently alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 6 carbon atoms, phenyl, phenyl substituted by alkyl of 1 to 18 carbon atoms, aralkyl of 7 to 9 carbon atoms or said aralkyl substituted by alkyl of 1 to 18 carbon atoms. R₂₆ and R₂₇ are the same or different and each is H, C₁-C₂₀ alkyl, C₃-C₂₀ alkenyl, C₅-C₁₂ cycloalkyl, C₇-C₁₃ aralkyl, C₆-C₁₀ aryl or R₂₆ and R₂₇, together with the nitrogen atom to which they are attached, form a 5-, 6- or 7-membered heterocyclic residue or R₂₆ and R₂₇ is each a residue of formula:

R₂₈X₃[(alkylene)O]n₁(alkylene)-)

wherein X₃ is O, S or N(R₂₈), R₂₈ is hydrogen or C₁-C₂₀ alkyl, “alkylene” is a C₁-C₁₂ alkylene residue and n₁ is 0 or an integer from 1 to 6. 8.0 Organoamine Tungstates from Polyamine Salts

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with an amine, carboxylate, sulfonate, dithiophosphate, naphthenates, phosphonates, phenoxy alkanoates, and N-acyl sarcosinates. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

A soluble acid salt of a carboxylic acid, a mono or disulfonic acid, naphthenic acid, dithiophosphoric acid or alkyl phosphonic acid with a polyamine is prepared in the first step and subsequently reacted with various tungsten sources as outlined above to the desired tungstate, which are oil soluble

In certain embodiments, long-chain monocarboxylic acids suitable for use in the present invention preferably contain at least 8, and more preferably at least 12, and up to 100 carbon atoms. In preferred embodiments, examples of suitable acids for use in the present invention include fatty acids such as coconut acid, hydrogenated coconut acid, menhaden acid, hydrogenated menhaden acid, tallow acid, hydrogenated tallow acid, and soya acid. Additional long-chain carboxylic acids that may be used include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid, behenic acid, erucic acid, oleic acid, linoleic acid, and linolenic acid. Mixtures of acids may also be used and are sometimes preferred. For example, commercial oleic acid is actually a mixture of many fatty acids ranging in carbon chain length from 14 to 20.

The sulfonic acid of the current invention could be one of the following:

1) An alkylated aryl sulfonic acid selected from the group consisting of

wherein R¹⁰ is H or an alkyl group containing up to 20 carbon atoms, and x is an integer from 0 to 2.

An alkylated aryl sulfonic acid selected from the group consisting of

wherein R₅₁, R₅₂, R₅₃ and R₅₄ are individually selected from the group consisting of hydrogen or essentially linear hydrocarbyl groups having about 9 to about 22 carbon atoms; and wherein l, m, n and p are integers from 0 to 4 and the sum of l+m+n+p is at least 1; and wherein R₅₁, R₅₂, R₅₃, and R₅₄ is a hydrogen where either l, m, n, or p is 0.

2) An alkylated aryl disulfonic acid selected from the group consisting of

and structure II

wherein each of R¹¹ and R¹² is the same or different and is a linear or branched alkyl group with 6 to 16 carbons, y is 0 to 3, z is 0 to 3 with the proviso that y+z is 1 to 4, n is 0 to 3, B is a divalent moiety selected from the group consisting of —C(R¹³)(R¹⁴)—, wherein each of R¹³ and R¹⁴ is H or independently a linear or branched alkyl group of 1-4 carbons and n is 1; —C(═O)—, wherein n is 1; —O— wherein n is 1; —S—, wherein n is 1 to 3; and —SO₂—, wherein n is 1;

Suitable sulfonic acids include alkane sulfonic acid, aralkyl sulfonic acid, including dodecyl benzene sulfonic acid, didodecyl benzenesulfonic acid, and sulfonic acids derived from various hydrocarbon feedstock. Examples of other suitable sulfonic acids include mono-, di-, and poly-alkylated naphthalenesulfonic acids, e.g., dinonyl napthalene sulfonic acid, didodecyl naphthalene sulfonic acids, diphenyl ether sulfonic acid, napthalene disulfide sulfonic acid, dicetyl thianthrene sulfonic acid, dialauryl betanaphthol sulfonic acid, dicapryl nitronaphthalene sulfonic acid, unsaturated paraffin wax sulfonic acid, hydroxy substituted paraffin wax sulfonic acid, tetraamylene sulfonic acid, mono- and poly-chlorosubstituted paraffin wax sulfonic acid, nitrosoparaffin wax sulfonic acid, cycloaliphatic sulfonic acid such as lauryl-cyclohexyl sulfonic acid, mono- and poly-wax-substituted cyclohexyl sulfonic acid, and the like. Suitable acid components include naphthenic acid, which encompasses a mixture of monobasic acids of cycloparaffins which are derived from either cyclopentane or cyclohexane and cyclopentane and a great variety of homologs and higher molecular weight analogs. Conventionally, the acids of commercial mixtures of naphthenic acids have molecular weights in the range of from about 180 to 350. Suitable acid components include dihydrocarbylphosphoric acids, dihydrocarbyldithiophosphoric acids, and dihydrocarbylmonothiophosphoric acids, from the following

wherein Y₁ and Y₂ are each independently of the other S or O R¹⁵ and R¹⁶ are each independently of the other H, C₃-C₁₈ alkyl, C₅-C₁₂ cycloalkyl, C₅-C₆ cycloalkylmethyl, C₉-C₁₀ bicycloalkylmethyl, C₉-C₁₀ tricycloalkylmethyl, phenyl, C₇-C₂₄-alkylphenyl, or R¹⁵ and R¹⁶ together are the group of the partial formula:

R¹⁵ and R¹⁶ defined as C₉-C₁₀ bicycloalkylmethyl are typically decalinylmethyl. R¹⁵ and R¹⁶ defined as C₉-C₁₀ tricycloalkylmethyl are preferably a group of formula:

R¹⁵ and R¹⁶ are preferably i-propyl, i-butyl, 2-ethylhexyl, octyl phenyl or oleyl. Suitable acid components also include an alkyl phenoxyalkanoic acid of the formula

wherein R^(q), R^(r), R^(s), R^(t) and R^(u) are, each independently of the other, hydrogen or C₁-C₂₀ alkyl and Q is a divalent C₁-C₂₀ hydrocarbon radical, saturated or unsaturated, selected from the group consisting of

Suitable acid components also include an N-acyl sarcosine derivative of the formula

wherein the acyl group R^(t)—C(═O)— is the residue of a fatty acid having 10 to 20 carbon atoms.

The polyamine compounds which may be employed in the production of the oil-soluble tungstate can be any suitable polyamine compound. In order to improve solubility of the organo tungstate product in base oils and finished oils, it is important for the mono-substituted diamine to have a high hydrocarbon character. For example, the diamine can be represented by the following general structure:

where x is 1 or 2, and R is a hydrocarbon-containing group containing a minimum of about 6 carbon atoms and up to 24 carbon atoms. R can be aliphatic or aromatic. R, in addition to the minimum of about 6 carbon atoms, may also contain oxygen, but preferably R does not include sulfur or additional nitrogen. It is preferred that R contains a minimum of 10 carbon atoms in order to further improve the organotungsten product solubility in base oil. The most preferred R contains oxygen in addition to the carbons, such as where R is an alkyloxyalkylene group. Where R represents an alkyloxyalkylene group, R can be represented by the structure —X₁—O—X₂, where X₁ is an alkylene of 2, 3 or 4 carbons and preferably is propylene or ethylene, and X₂ is an alkyl moiety having 3 to 30 carbon atoms, more preferably an alkyl moiety having 7 to 20 carbon atoms, and where X₂ can be a straight or branched, saturated or partially unsaturated hydrocarbon chain. The use of a diamine including an R group represented by —X₁—O—X₂ as defined herein in the reaction process makes it possible to maximize the level of tungsten incorporation levels in the oil soluble reaction product while performing the process without the use of volatile organic processing solvents.

Examples of some mono-substituted diamines that may be used include phenylaminopropylamine, hexylaminopropylamine, benzylaminopropylamine, octylaminopropylamine, octylaminoethylamine, dodecylaminopropylamine, dodecylaminoethylamine, hexadecylaminopropylamine, hexadecylaminoethylamine, octadecylaminopropylamine, octadecylaminoethylamine, isopropyloxypropyl-1,3-diaminopropane, octyloxypropyl-1,3-diaminopropane, decyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, dodecyloxypropyl-1,3-diaminopropane, tetradecyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, isododecyloxypropyl-1,3-diaminopropane, isotridecyloxypropyl-1,3-dia-minopropane. Mono-substituted diamines derived from fatty acids may also be used. Examples include N-coco alkyl-1,3-propanediamine (Duomeen C), N-tallow alkyl-1,3-propanediamine (Duomeen T), and N-oleyl-1,3-propanediamine (Duomeen OL), all obtained from Akzo Nobel.

Especially preferred polyamine compounds include diamine 1,3-diaminopropane having an alkyl moiety selected from the group consisting of N-coco, N-tallow, N-soya and N-oleyl. The compound 1,3-diaminopropane can be represented by the general formula R—NH(C₃H₆NH₂) wherein R is an alkyl group representing the coco, tallow, soya or oleyl moiety.

Other suitable polyamines include tetraethylene pentamine and similar polyamine types containing primary and/or secondary amine groups. Further suitable polyamines can be represented by the general formulas R(NH₂)₂ and R NH—(C₃H₆NH₂)₂ wherein R is an alkyl radical derived from the dimerization of a C₁₈ unsaturated fatty acid. Another group of suitable polyamine compounds can be represented by the general formula R—N—(C₃H₆NH₂)₂ wherein R is an alkyl radical derived from tallow, oleyl and lauryl fatty acids.

Other useful amine compounds include alicyclic diamines such as 1,4-di-(aminomethyl)cyclohexane, and heterocyclic nitrogen compounds such as imidazolines, and N-aminoalkyl piperazines of the general formula:

wherein p₁ and p₂ are the same or different and each is an integer from 1 to 4, and e, f and o are the same or different and each is an integer from 1 to 3.

in which n=2 or 3, m=1 or 2, R^(a), R^(b) and R^(c) are identical or different, and represent hydrogen, alkyl, or substituted alkyl, hydroxyalkyl, aryl, aralkyl, cycloalkyl, heterocyclics, ether, thioether, halogen, —N(R)₂, polyethylene polyamines, nitro groups, keto groups, ester groups, or carbonamide groups, alkyl substituted with the various functional groups described above, and T represents alkyl, alkylene, aryl, aralkyl, cycloalkyl or heterocyclic radical, substituted if desired with halogen, nitro groups, alkyl groups, alkoxy groups or amino groups, and, when m=1, represents also hydrogen. Salts of the above structures include carboxylic including aliphatic, aromatic and poly carboxylic, carbonic, sulfonic and phosphoric acid salts. R^(a), R^(b), R^(c) are independently hydrogen, alkyl, alkenyl or alkoxy of 1 to 36 carbons, cycloalkyl of 6 to 32 carbons or alkylamino of 1 to 36 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenyl, hydroxyalkyl or hydroxycycloalkyl of 1 to 20 carbon atoms, methoxyalkyl of 1 to 20 carbon atoms, aralkyl of 7 to 9 carbon atoms, where the aryl group of the aralkyl group is further substituted by alkyl of 1 to 36 carbon atoms. When m=2, T is alkylene of 1 to 12 carbons or arylene of 6 to 10 carbons, or a plurality of radicals being able to be joined, containing hetero atoms also by hetero atoms such as O, N or S, if desired. Preferred imidazoline structures are where R is a long chain alkyl up to 18 carbon atoms, m=1 and R^(c) is one of 2-hydroxyethyl, or 2-aminoethyl or 2-amido ethyl substituents. Examples of such amines include 2-pentadecyl imidazoline, aminoethyl oleyl imidazoline and N-(2-aminoethyl) piperazine.

Ammonium molybdates derived from these precursor salts that are a component of the present invention may also be prepared from a molybdenum source. The process for preparing the organoammonium molybdates of the invention involves the use of one of several molybdenum sources including molybdenum trioxide, ammonium paramolybdate or ammonium heptamolybdate. A preferred molybdenum source is molybdenum trioxide. The use of molybdenum trioxide results in effective molybdenum incorporation into the organic ligand made by the aforementioned first process step, and it produces a reaction mass by the completion of the second step that does not require filtration.

9.0 Organoammonium Tungstates from the Reaction Product of Mono Carboxylic Acid with Diamines, Fatty Oil with Diamines and Naphthenyl, Alkylphenoxyalkanoyl and N-Sarcosoyl Polyamines.

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with the reaction product of a mono carboxylic acid, fatty oil, vegetable oil, triglyceride or glycerol esters of fatty acids, naphthenic acid, alkylphenoxy alkanoic acid or N-acyl sarcosine with a mono substituted alkylene diamine. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

In certain embodiments, examples of long-chain monocarboxylic acids suitable for use in the present invention preferably contain at least 8, and more preferably at least 12, and up to 100 carbon atoms. In preferred embodiments, examples of suitable acids for use in the present invention include fatty acids such as coconut acid, hydrogenated coconut acid, menhaden acid, hydrogenated menhaden acid, tallow acid, hydrogenated tallow acid, and soya acid. Additional long-chain carboxylic acids that may be used include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid, behenic acid, erucic acid, oleic acid, linoleic acid, and linolenic acid. Mixtures of acids may also be used and are sometimes preferred. For example, commercial oleic acid is actually a mixture of many fatty acids ranging in carbon chain length from 14 to 20.

Examples of preferred fatty or vegetable oils that may be used in the process of the present invention include groundnut oil, coconut oil, linseed oil, palm kernel oil, olive oil, cottonseed oil, grapeseed oil, corn oil, canola oil, palm oil, peanut oil, safflower seed oil, sesame seed oil, caster oil, rapeseed oil (low or high erucic acids), soyabean oil, sunflower oil, herring oil, sardine oil, lard, menhaden oil, hazel nut oil, walnut oil, and tallow, and mixtures thereof. These fatty or vegetable oils can include those compounds generally known as triglycerides, which have the general structure as shown below

where R′, R″, or R′″ independently represent saturated or unsaturated aliphatic hydrocarbon groups having from about 8 to about 22 carbon atoms, and preferably are hydrocarbon chains having about 12 to about 22 carbon atoms. Mono- and diglycerides, either separately or in mixtures with one or more triglycerides, are also useful as fatty or vegetable oils in the present invention, in which the R′, R″, or R′″ groups present have the same above meaning.

Suitable acid components include naphthenic acid, which encompasses a mixture of monobasic acids of cycloparaffins which are derived from either cyclopentane or cyclohexane and cyclopentane and a great variety of homologs and higher molecular weight analogs. Conventionally, the acids of commercial mixtures of naphthenic acids have molecular weights in the range of from about 180 to 350.

Suitable acid components also include an alkyl phenoxyalkanoic acid of the formula

wherein R^(q), R^(r), R^(s), R^(t) and R^(u) are, each independently of the other, hydrogen or C₁-C₂₀ alkyl and Q is a divalent C₁-C₂₀ hydrocarbon radical, saturated or unsaturated, selected from the group consisting of

Suitable acid components also include an N-acyl sarcosine derivative of the formula

wherein the acyl group R^(t)—C(═O)— is the residue of a fatty acid having 10 to 20 carbon atoms.

The polyamine compounds which may be employed in the production of the oil-soluble sulfonate tungstate can be any suitable polyamine compound. In order to improve solubility of the organo tungstate product in base oils and finished oils, it is important for the mono-substituted diamine to have a high hydrocarbon character. For example, the diamine can be represented by the following general structure:

where x is 1 or 2, and R is a hydrocarbon-containing group containing a minimum of about 6 carbon atoms and up to 24 carbon atoms. R can be aliphatic or aromatic. R, in addition to the minimum of about 6 carbon atoms, may also contain oxygen, but preferably R does not include sulfur or additional nitrogen. It is preferred that R contains a minimum of 10 carbon atoms in order to further improve the organotungsten product solubility in base oil. The most preferred R contains oxygen in addition to the carbons, such as where R is an alkyloxyalkylene group. Where R represents an alkyloxyalkylene group, R can be represented by the structure —X₁—O—X₂, where X₁ is an alkylene of 2, 3 or 4 carbons and preferably is propylene or ethylene, and X₂ is an alkyl moiety having 3 to 30 carbon atoms, more preferably an alkyl moiety having 7 to 20 carbon atoms, and where X₂ can be a straight or branched, saturated or partially unsaturated hydrocarbon chain. The use of a diamine including an R group represented by —X₁—O—X₂ as defined herein in the reaction process makes it possible to maximize the level of tungsten incorporation levels in the oil soluble reaction product while performing the process without the use of volatile organic processing solvents.

Examples of some mono-substituted diamines that may be used include phenylaminopropylamine, hexylaminopropylamine, benzylaminopropylamine, octylaminopropylamine, octylaminoethylamine, dodecylaminopropylamine, dodecylaminoethylamine, hexadecylaminopropylamine, hexadecylaminoethylamine, octadecylaminopropylamine, octadecylaminoethylamine, isopropyloxypropyl-1,3-diaminopropane, octyloxypropyl-1,3-diaminopropane, decyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, dodecyloxypropyl-1,3-diaminopropane, tetradecyloxypropyl-1,3-diaminopropane, isodecyloxypropyl-1,3-diaminopropane, isododecyloxypropyl-1,3-diaminopropane, isotridecyloxypropyl-1,3-diaminopropane. Mono-substituted diamines derived from fatty acids may also be used. Examples include N-coco alkyl-1,3-propanediamine (Duomeen C), N-tallow alkyl-1,3-propanediamine (Duomeen T), and N-oleyl-1,3-propanediamine (Duomeen OL), all obtained from Akzo Nobel. Especially preferred are polyamine compounds including diamine 1,3-diaminopropane having an alkyl moiety selected from the group consisting of N-coco, N-tallow, N-soya and N-oleyl. The compound 1,3-diaminopropane can be represented by the general formula R—NH(C₃H₆NH₂) wherein R is an alkyl group representing the coco, tallow, soya or oleyl moiety.

Other suitable polyamines include tetraethylene pentamine and similar polyamine types containing primary and/or secondary amine groups. Further suitable polyamines can be represented by the general formulas R(NH₂)₂ and R NH—(C₃H₆NH₂)₂ wherein R is an alkyl radical derived from the dimerization of a C₁₈ unsaturated fatty acid. Another group of suitable polyamine compounds can be represented by the general formula R—N—(C₃H₆NH₂)₂ wherein R is an alkyl radical derived from tallow, oleyl and lauryl fatty acids.

10.0 Organoammonium Tungstates from the Reaction Product of Substituted Succinic Anhydrides with Polyamines

The organoamine tungstate compounds useful in the present invention may be prepared by a variety of methods. One method involves reacting a sulfur and phosphorus-free tungsten source with the reaction product of substituted succinic anhydrides with polyamines. Examples of sulfur- and phosphorus-free tungsten sources include tungstic acid, tungsten trioxide, ammonium ortho tungstate, ammonium meta tungstate, ammonium paratungstate, sodium tungstate and potassium tungstate.

Succinimides of the current invention may be represented by the following general formula.

where R¹⁸ is a C6 to C30 isomerized alkenyl group, represented by:

(where g and h are integers whose sum is from 1 to 25), or its fully saturated alkyl analog, R¹⁷ is an alkyl group, aryl group, containing one or more nitrogen atom and other heteroatoms. The succinimides of the present invention are those produced from succinic anhydrides substituted with isomerized alkenyl groups or their fully saturated alkyl analogs. Preparation of isomerized alkenyl succinic anhydrides is described in, for example, U.S. Pat. No. 3,382,172, hereby incorporated by reference in its entirety. Often these materials are prepared by heating alpha-olefins with acidic catalysts to migrate the double bond to form an internal olefin. This mixture of olefins (2-enes, 3-enes, etc.) is then thermally reacted with maleic anhydride.

Typically olefins from C₆ (e.g. 1-hexene) to C₃₀ (e.g. 1-tricosane) are used. Suitable isomerized alkenyl succinic anhydrides of structure (1)

include isodecylsuccinic anhydride (x+y=5), iso-dodecylsuccinic anhydride (x+y=7), iso-tetradecylsuccinic anhydride (x+y=9), iso-hexadecylsuccinic anhydride (x+y=11), iso-octadecylsuccinic anhydride (x+y=13) and isoeicosylsuccinic anhydride (x+y=15). Preferred materials are isohexadecylsuccinic anhydride and iso-octadecylsuccinic anhydride.

The materials produced by this process contain one double bond (alkenyl group) in the alkyl chain. The alkenyl substituted succinic anhydrides may be easily converted to their saturated alkyl analogs by hydrogenation.

Suitable primary and secondary amines useful to produce the succinimides are represented by structure

where R²⁵, R²⁶, and R²⁷ are independently selected from the group consisting of H, C₁ to C₂₅ straight or branched chain alkyl radicals, C₁ to C₁₂ alkoxy radicals; C₂ to C₆ alkylene radicals; u is an integer from 1 to 6, preferably 2 to 4; and v is an integer from 0 to 10, preferably from 1 to 4.

Bis succinimides of the current invention may be represented by the following general formula

wherein, R²¹ and R²² may be identical or different from each other and are each hydrocarbon groups having 5 or more carbons; R²³ is a divalent hydrocarbon group having 1 to 5 carbons; R²⁴ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbons; and n is an integer in the range of 0 to 10. In the above general formula, R²¹ and R²² may be the same as each other or different from each other, and are each saturated or unsaturated hydrocarbon groups having 5 or more carbons, preferably 5 to 40 carbons. Examples of hydrocarbon groups include pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, hexadecyl groups, heptadecyl groups, octadecyl groups, nonadecyl groups, oleyl groups and other hydrocarbon groups having up to 40 carbons. Preferred hydrocarbon groups include straight chain hydrocarbon groups having between 8 and 25 carbons. In the above general formula, R²³ is a divalent hydrocarbon group having 1 to 5 carbons, preferably an alkylene group having 2 or 3 carbons.

In the above general formula, R²⁴ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbons. Examples of hydrocarbon groups include alkyl groups having 1 to 20 carbons; alkenyl groups having 2 to 20 carbons; cycloalkyl groups having 6 to 20 carbons; and aryl groups having 6 to 20 carbons. The aryl groups may have an alkyl group having 1 to 12 carbons. Hydrogen atoms and alkyl groups having 1 to 10 carbons are particularly preferred as R²⁴. Groups having a number of (i.e. 1 to 5 of each) amino groups and/or amide bonds in their structure can be used as the above-described hydrocarbon groups.

The amino groups are represented by —NH— or —NH₂; and the amide bonds are represented by

They may be bonded with the carbons of the hydrocarbon group at an arbitrary position.

The bis succinimides of the present invention are those produced from succinic anhydrides substituted with isomerized alkenyl groups or their fully saturated alkyl analogs, and polyamines. Suitable polyamines are saturated amines of the general formula:

where R²⁵, R²⁶, and R²⁷ are independently selected from the group consisting of H, C₁ to C₂₅ straight or branched chain alkyl radicals, C₁ to C₁₂ alkoxy radicals; C₂ to C₆ alkylene radicals; u is an integer from 1 to 6, preferably 2 to 4; and v is an integer from 0 to 10, preferably from 1 to 4.

Non-limiting examples of suitable polyamine compounds include: 1,6-diaminohexane, diethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene hexamine. Useful mixtures of polyamines having from 5 to 7 nitrogen atoms per molecule are available from Dow Chemical Co. as Polyamine H, Polyamine 400 and Polyamine E-300.

Polyoxyalkylene amines are also useful in this invention and are shown as structure

H₂N-alkylene-(—O-alkylene-)u₁-NH₂

where u₁ is an integer of from 1 to 10. The polyamines have molecular weights from about 100 to 500. The preferred polyoxyalkylene polyamines include polyoxyethylene and polyoxypropylene diamines and the polyoxypropylene triamines. Commercial polyoxyalkylene amines are available from Jefferson Chemical Co. sold under the trade name “Jeffamines D-230, D-400, D-1000, T-430,” etc.

Organo ammonium molybdates derived from these precursor succinimides according to the invention may also be prepared from one of various molybdenum sources. The process for preparing the organoammonium molybdates of the invention involves the use of one of several molybdenum sources including molybdenum trioxide, ammonium paramolybdate or ammonium heptamolybdate. A preferred molybdenum source is molybdenum trioxide. The use of molybdenum trioxide results in effective molybdenum incorporation into the organic ligand made by the aforementioned first process step, and it produces a reaction mass by the completion of the second step that does not require filtration. There is no particular restriction on the type of secondary diarylamine used in the invention as an antioxidant. Preferably, the secondary diarylamine antioxidant has the general formula:

wherein R₂₂ and R₂₃ each independently represents a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms. Illustrative of substituents for the aryl include aliphatic hydrocarbon groups such as alkyl having from about 1 to 20 carbon atoms, hydroxy, carboxyl or nitro, e.g., an alkaryl group having from 7 to 20 carbon atoms in the alkyl group. The aryl is preferably substituted or unsubstituted phenyl or naphthyl, particularly wherein one or both of the aryl groups are substituted with an alkyl such as one having from 4 to 30 carbon atoms, preferably from 4 to 18 carbon atoms, most preferably from 4 to 9 carbon atoms. It is further preferred that one or both aryl groups be substituted, e.g. mono alkylated diphenylamine, dialkylated diphenylamine, or mixtures of mono- and di-alkylated diphenylamines.

The secondary diarylamines used in this invention can be of a structure other than that shown in the above formula which shows but one nitrogen atom in the molecule. Thus, the secondary diarylamine can be of a different structure provided that at least one nitrogen has 2 aryl groups attached thereto, e.g., as in the case of various diamines having a secondary nitrogen atom as well as two aryls on one of the nitrogens. The secondary diarylamines used in this invention preferably have antioxidant properties in lubricating oils, even in the absence of the tungsten compound.

It is preferred that the oil-soluble secondary aromatic amines are diphenylamines of general formula:

wherein D₁ and D₂ may be the same or different and each independently represents a hydrocarbyl radical as hereinbefore defined. It is preferred that D₁ and D₂ are C₁ to C₂₈ aliphatic hydrocarbyl radicals. E and F may be the same or different and may equal 0, 1, 2 or 3. It is preferred that E and F are the same and that they equal 1. It is also preferred that the diphenylamines have a nitrogen content of between 2.5 and 5% by weight. It is preferred that D₁ and D₂ are located in the meta or para positions relative to the amino substitution in the aromatic rings of the diphenylamines. Examples of suitable diphenylamines include di-octyldiphenylamine, t-pentyldiphenylamine, diisobornyldiphenylamine, didecyldiphenylamine, didodecyldiphenylamine, dihexyldiphenylamine, di-t-butyldiphenylamine, di-t-octyldiphenylamine, dinonylamine, dibutyldiphenylamine, distyryldiphenylamine. Other suitable diphenylamines include di-substituted derivatives wherein the D₁ and D₂ are different and independently represent hydrocarbyl radicals, such as t-butyl, t-octyl, styryl, n-butyl or n-octyl for example. Some of these diphenylamines are commercially available and are sold under the trademarks, VANLUBE™ DND, NAUGALUBE™ 438L, PEARSALL™ OA502, LUBRIZOL™ 5150A, VANLUBE™ SL, NAUGALUBE™ 680, INGANOX™ L-57 and VANLUBE™ 848. VANLUBE™ DND, NAUGALUBE™ 438L, PEARSALL™ OA502 and LUBRIZOL™ 5150A nominally have structures as represented by the above formula wherein D₁ and D₂ are C₉ hydrocarbyl groups and E=F=1. VANLUBE™ SL and NAUGALUBE™ 680 nominally have structures as represented by above formula wherein D₁ and D₂ are either one of C₄, C₈ or styryl hydrocarbyl groups and E=F=1; these are mixed diphenyl amines. IRGANOX™ L-57 and VANLUBE™ 848 nominally have structures as represented by above formula wherein D₁ and D₂ are either one of t-butyl or t-octyl groups and E=F=1.

Other secondary diarylamines used in this invention soluble in the formulated crankcase oil package include: diphenylamine; various alkylated diphenylamines; 3-hydroxydiphenylamine; N-phenyl-1,2-phenylenediamine; N-phenyl-1,4-phenylenediamine; monobutyldiphenylamine; dibutyldiphenylamine; monooctyldiphenylamine; monononyldiphenylamine; dinonyldiphenylamine; monotetradecyldiphenylamine; ditetradecyldiphenylamine; phenyl-alpha-naphthylamine; monooctyl phenyl-alpha-naphthylamine; phenyl-beta-naphthylamine; monoheptyldiphenylamine; diheptyldiphenylamine; p-oriented styrenated diphenylamine; mixed butyloctyldiphenylamine; and mixed octylstryryldiphenylamine, and mixtures thereof. Other examples of commercial diarylamines include, for example, IRGANOX™ L06, IRGANOX™ L57 (mixed butyloctyl diphenyl amine) and IRGANOX™ L67 from Ciba Specialty Chemicals; NAUGALUBE™ AMS, NAUGALUBE™ 438, NAUGALUBE™ 438R, NAUGALUBE™ 438L, NAUGALUBE™ 500, NAUGALUBE™ 640, NAUGALUBE™ 680, and NAUGARD™ PANA from Crompton Corporation; GOODRITE™ 3123, GOODRITE™ 3190×36, GOODRITE™ 3127, GOODRITE™ 3128, GOODRITE™ 3185X1, GOODRITE™ 3190×29, GOODRITE™ 3190×40, GOODRITE™ 3191 and GOODRITE™ 3192 from Noveon Specialty Chemicals; VANLUBE™ DND, VANLUBE™ NA, VANLUBE™ PNA, VANLUBE™ SL (mixed octylstyryl diphenylamine), VANLUBE™ SLHP, VANLUBE™ SS, VANLUBE™ 81, VANLUBE™ 848, and VANLUBE™ 849, VANLUBE™ 961 (mixed butyloctyl diphenyl amine) from R. T. Vanderbilt Company Inc, LUBRIZOL™ 5150A & C from LUBRIZOL™, and NA-LUBE™ AO-140 (mixed butyloctyl diphenyl amine), NA-LUBE™ AO-150 (mixed octylstyryl diphenylamine), from King Industries.

The concentration of the secondary diarylamine in the lubricating composition can vary from about 0.075 to 2.5 wt %, depending upon the application. A practical diarylamine use range in the lubricating composition is from about 750 parts per million to 5,000 parts per million (i.e. 0.075 to 0.5 wt %), preferably from 1,000 to 4,000 parts per million (ppm) and even more preferably from about 1,200 to 3,000 ppm

Preferably, the quantity of tungsten is relation to the quantity of the secondary amine should be within a certain ratio. The quantity of tungsten should be about 0.020 to 0.6 parts by weight for each part by weight of the amine in the lubricating oil composition. Preferably, this ratio will be from about 0.040 to 0.40 parts of the tungsten per part of the amine and particularly about 0.05 to 0.3 parts of the tungsten per part of the amine. The total quantity of tungsten and amine can be provided by one or more than one tungsten or amine compound.

An alkylated phenothiazine suitable for this invention is preferably oil soluble or dispersible and preferably corresponds to the general formula below where the substituents R₁₁-R₁₄ could contain heteroatoms,

R₁₁ and R₁₂ are hydrogen or together form a fused six-membered aromatic ring; one of R₁₃ and R₁₄ is hydrogen and the other is C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl, —C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl; or both R₁₃ and R₁₄ are C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl-C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl, if R₁₁ and R₁₂ hydrogen; or R₁₃ is hydrogen and R₁₄ is C₂-C₃₀ alkyl, cyclo-C₅-C₁₂ alkyl C₂-C₄ alkyl, α-C₁-C₂ alkylbenzyl or α,α-dimethylbenzyl, if R₁₁ and R₁₂ together form a fused six-membered aromatic ring, R₁₅ is hydrogen, C₁-C₁₂ alkyl, benzyl, allyl, methallyl, phenyl or a group —CH₂SR₄, where R₄ is C₄-C₁₈ alkyl, —CH₂CH₂COO(C₄-C₁₈ alkyl), or an alkylene, aralkylene bridging two phenothiazine moieties.

Typical examples of alkylphenothiazine include but are not limited to monotetradecylphenothiazine, ditetradecylphenothiazine, monodecylphenothiazine, didecylphenothiazine monononylphenothiazine, dinonylphenothiazine, monoctylphenothiazine and dioctylphenothiazine.

The antioxidant lubrication compositions of the present invention may optionally contain additional friction modifiers, antioxidants and/or copper corrosion inhibitors. Embodiments of friction modifiers which may optionally be added can be found for example in U.S. Pat. Nos. 4,792,410 and 5,110,488, which are incorporated herein by reference in their entirety and include fatty phosphites, fatty acid amides, fatty epoxides, borated fatty epoxides, fatty amines, glycerol esters, borated glycerol esters, alkoxylated fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, sulfurized olefins, fatty imidazolines and mixtures thereof.

Embodiments of antioxidants which may optionally be added include hindered phenolic antioxidants, secondary aromatic amine antioxidants, sulfurized phenolic antioxidants, oil-soluble copper compounds, phosphorus-containing antioxidants, organic sulfides, disulfides and polysulfides.

Embodiments of copper corrosion inhibitors which may optionally be added include thiazoles, triazoles and thiadiazoles. Example embodiments of such compounds include benzotriazole, tolyltriazole, octyltriazole, decyltriazole, dodecyltriazole, 2-mercapto benzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazoles, 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazoles, 2,5-bis(hydrocarbylthio)-1,3,4-thiadiazoles, and 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazoles.

The organotungsten compound, alkylated diphenylamine and sulfur containing compound can either be added individually to a base oil to form the lubricating composition of the invention or they can be premixed to form a composition which can then be added to the base oil. The resulting lubricating composition preferably comprises a major amount (i.e. at least 90% by weight) of base oil and a minor amount (i.e. less than 10% by weight) of the additive composition.

In another aspect the invention provides for a lubricating oil composition which comprises lubricating oil and a lubricating oil additive comprising the combination of an oil-soluble tungsten compound and at least one oil-soluble aromatic amine. The concentration of the lubricating oil additive is typically in the range of 0.01 to about 15% by weight based on the total weight of the composition and is preferably from about 0.1 to about 7% by weight.

Suitable lubricating oils for use in preparing the lubricating composition include those oils which are conventionally employed as crankcase lubricating oils for internal combustion engines and those which may be employed as power transmitting fluids such as automatic transmission fluids, hydraulic fluids, or gear lubricants.

The lubricating oil may be a synthetic oil such as for example alkylesters of dicarboxylic acids, polyglycols and alcohols, polyalphaolefins, alkylbenzenes, alkyl naphthalenes, organic esters of phosphoric acids, or polysilicone oils. The lubricating oil may be a natural oil including mineral oils which may vary widely as to their crude source e.g. whether paraffinic, naphthenic or mixed paraffinic-naphthenic; as well as to their formation, e.g. distillation range, straight run or cracked, hydrorefined, or solvent extracted.

The invention further provides a lubricating oil concentrate. In the preparation of lubricating oil compositions it is a convenient practice to introduce additives in the form of a concentrate; which introduction may be made by methods known in the art. The lubricating oil concentrate may contain between 2.5 to 90 weight percent more preferably 5 to 75 weight percent of the additive composition in a suitable solvent. Suitable solvents may include hydrocarbon oils (e.g. mineral lubricating oil or synthetic oil).

The ratio of tungsten compound to the oil-soluble aromatic amine may be selected so as to provide an antioxidant effect of sufficient magnitude to meet the end use requirements of the lubricating oil—for example, to achieve adequate performance in the Sequence III E engine test for crankcase lubricating oils (according to the procedure of ASTM STP315). Preferably the tungsten compound and the oil-soluble aromatic amine are employed in a ratio of from 1:10 to 10:1 (by wt), more preferably from 3:1 to 1:3 (by wt).

The lubricating oil additive may be used as the sole additive for the composition or concentrate or may be used in combination with several different types of additives which may be required to fulfill other requirements of the composition or concentrate during use. The composition may be used as a crankcase lubricating oil, a cylinder lubricant for applications such as marine diesel, industrial oil, functional fluid such as power transmission fluid, tractor oil, gear oil or hydraulic fluid. Accordingly the compositions or concentrates of the invention may in addition to the lubricating oil additive contain one or more of the following:

(a) a dispersant, preferably an ashless dispersant;

(b) a metal containing detergent, preferably having a high total base number;

(c) an antiwear and/or extreme pressure additive;

(d) a viscosity index improver, which may also have dispersant properties;

(e) a pour point depressant;

(f) a corrosion inhibitor and/or metal deactivator; and

(g) a friction modifier or fuel economy agent,

as well as other additives such as demulsifiers, seal swell agents, or even supplementary antioxidants.

Where such compositions are for use as crankcase lubricants they preferably contain at least an ashless dispersant and/or a viscosity index improver dispersant, a detergent, and an antiwear additive in amounts effective to provide their respective functions.

Dispersants

The preferred ashless dispersant in the compositions and concentrates of this invention is a long chain hydrocarbyl substituted mono- or di-carboxylic acid material, (i.e. acid, anhydride, or ester) and includes a long chain hydrocarbon, generally a polyolefin, substituted with an alpha or beta unsaturated C4 to C10 carboxylic acid material, such as itaconic acid, maleic acid, maleic anhydride, chloromaleic acid, dimethyl fumarate, chloromaleic anhydride, acrylic acid, methacrylic acid, crotonic acid, or cinnamic acid. Preferably, the dispersant contains at least about 1 mole (e.g. 1.05 to 1.2 moles, or higher) of the acid material per mole of polyolefin. The proportion of the dispersant is preferably from 1 to 10, and even more preferably 3 to 7 weight percent of the lubricating oil.

Preferred olefin polymers for the reaction with carboxylic acids are polymers derived from a C2 to C5 monoolefin. Such olefins include ethylene, propylene, butylene, isobutylene, pentene, oct-1-ene or styrene. The polymers may be homopolymers such as polyisobutylene or copolymers of two or more of such olefins. These include copolymers of ethylene and propylene; butylene and isobutylene; propylene and isobutylene; etc. Other copolymers include those in which a minor molar amount of the copolymer monomers (e.g. 1 to 10 mole percent), is a C4 to C18 diolefin, (e.g., a copolymer of isobutylene and butadiene; or a copolymer of ethylene, propylene and 1,4-hexadiene; etc).

In some cases, the olefin polymer may be completely saturated, for example an ethylene-propylene copolymer made by a Ziegler-Natta synthesis using hydrogen as a moderator to control molecular weight.

The olefin polymers usually have number average molecular weights above about 700, including number average molecular weights within the range of from 1,500 to 5,000 with approximately one double bond per polymer chain. An especially suitable starting material for a dispersant additive is polyisobutylene. The number average molecular weight for such polymers can be determined by several known techniques. A convenient method for such determination is by gel permeation chromatography (GPC) which additionally provides molecular weight distribution information. (see W. W. Yau, J. J. Kirkland and D. D. Bly, “Modern Size Exclusion Liquid Chromatography,” John Wiley and Sons, New York, 1979).

Processes for the reaction of the olefin polymer with the unsaturated carboxylic acid, anhydride, or ester are known in the art. For example, the olefin polymer and the carboxylic acid material may be simply heated together as disclosed in U.S. Pat. Nos. 3,361,673 and 3,401,118 (hereby incorporated by reference in their entirety) to cause a thermal “ene” reaction to take place. Alternatively, the olefin polymer can be first halogenated, for example chlorinated or brominated, to about 1 to 8, preferably 3 to 7, weight percent chlorine or bromine, based on the weight of polymer, by passing chlorine or bromine through the polyolefin at a temperature of 100° C. to 250° C., e.g. 120° C. to 160° C., for about 0.5 to 10 hours, more preferably 1 to 7 hours. The halogenated polymer may then be reacted with sufficient unsaturated acid or anhydride at 100° to 250° C., usually 180° C. to 220° C., for 0.5 to 10 hours, more preferably 3 to 8 hours. Processes of this general type are taught in U.S. Pat. Nos. 3,087,436; 3,172,892; 3,272,746, hereby incorporated by reference in their entirety.

Alternatively, the olefin polymer and the unsaturated acid or anhydride are mixed and heated while chlorine is added to the hot material. Processes of this type are disclosed in U.S. Pat. Nos. 3,215,707; 3,231,587; 3,912,764; 4,110,349; 4,234,435; and GB-A-1 440 219, all of which are incorporated by reference in their entirety.

When a halogen is used, from 65 to 95 weight percent of the polyolefin normally reacts with the carboxylic acid or anhydride. Thermal reactions, carried out without the use of halogen or a catalyst, cause only from 50 to 75 weight percent of the polyisobutylene to react. Chlorination increases reactivity.

The carboxylic acid or anhydride can then be further reacted with amines, alcohols, including polyols, amino-alcohols, etc., to form other useful dispersant additives. Thus if the acid or anhydride is to be further reacted, (e.g. neutralized) then generally a major proportion of at least 50 percent of the acid units up to all the acid units will be reacted.

The ashless dispersants useful in this invention are polyisobutenyl succinimides formed from polyisobutenyl succinic anhydride and an alkylene polyamine such as triethylene tetramine or tetraethylene pentamine, wherein the polyisobutenyl substituent is derived from polyisobutene having a number average molecular weight preferably in the range of 700 to 1200 more preferably from 900 to 1100. It has been found that selecting certain dispersants within the broad range of alkenyl succinimides produces fluids with improved frictional characteristics. The most preferred dispersants of this invention are those wherein the polyisobutene substituent group has a molecular weight of approximately 950 atomic mass units, the basic nitrogen containing moiety is polyamine (PAM) and the dispersant has been post treated with a boronating agent.

The ashless dispersants of the invention can be used in any effective amount. However, they are typically used from about 0.1 to 10.0 mass percent in the finished lubricant, preferably from about 0.5 to 7.0 percent, and most preferably from about 2.0 to about 5.0 percent.

Useful amine compounds for reaction with the hydrocarbyl substituted carboxylic acid or anhydride include mono- and polyamines with preferably 2 to 60, and more preferably 3 to 20, total carbon atoms and from 1 to 12, and more preferably 2 to 8 nitrogen atoms in a molecule. These amines may be hydrocarbyl amines or may be hydrocarbyl amines including other groups, e.g. hydroxy groups, alkoxy groups, amide groups, nitriles, or imidazoline groups. Hydroxy amines with 1 to 6 hydroxy groups, preferably 1 to 3 hydroxy groups, are particularly useful. Preferred amines are aliphatic saturated amines, including those of the general formulae:

wherein R²⁸, R²⁹ and R³⁰ are each independently hydrogen; C₁ to C₂₅ straight or branched chain alkyl radicals; C₁ to C₁₂ alkoxy-(C₆ alkylene) radicals; or C₂ to C₁₂ alkylamino-C₂ to C₆ alkylene) radicals; each s₁ can be the same or a different number of from 2 to 6, preferably 2 to 4; and w is a number from 0 to 10, preferably 2 to 7. Preferably at least one of R²⁸, R²⁹ and R³⁰ is hydrogen.

Suitable amines include 1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethylene amines such as diethylene triamine; triethylene tetramine; tetraethylene pentamine; polypropylene amines such as 1,2-propylene diamine; di-(1,2-propylene)triamine; di(1,3-propylene)-triamine; N,N-dimethyl-1,3-diaminopropane; N,N-di-(2-aminoethyl) ethylene diamine; N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propane diamine; tris hydroxymethylaminomethane (THAM); diisopropanol amine; diethanol amine; triethanol amine; amino morpholines such as N-(3-amino-propyl) morpholine; etc.

Other useful amine compounds include alicyclic diamines such as 1,4-di-(aminomethyl) cyclohexane, and heterocyclic nitrogen compounds such as imidazolines, and N-aminoalkyl piperazines of the general formula:

wherein p₁ and p₂ are the same or different and each is an integer from 1 to 4, and e, f and o are the same or different and each is an integer from 1 to 3. Examples of such amines include 2-pentadecyl imidazoline and N-(2-aminoethyl) piperazine.

Hydroxyamines which can be reacted with the long chain hydrocarbon substituted dicarboxylic acid material mentioned above to form dispersants include 2-amino-1-butanol, 2-amine-2-methyl-1-propanol, p-(beta-hydroxyethyl)-aniline, 2-amino-1-propanol, 3-amino-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, N-(beta-hydroxy propyl)N′-(beta-aminoethyl)-piperazine, ethanolamine and beta-(beta-hydroxyethoxy)-ethylamine. Mixtures of these or similar amines can also be employed. Commercial mixtures of amine compounds may advantageously be used. For example, one process for preparing alkylene amines involves the reaction of an alkylene dihalide (such as ethylene dichloride or propylene dichloride) with ammonia, which results in a complex mixture of alkylene amines wherein pairs of nitrogens are joined by alkylene groups, forming such compounds as diethylene triamine, triethylene tetramine, tetraethylene pentamine and corresponding piperazines. Useful poly(ethyleneamine) compounds averaging about 5 to 7 nitrogen atoms per molecule are available commercially under trade names such as “Polyamine H”, “Polyamine 400”, “Dow Polyamine E-100”, etc.

Useful amines also include polyoxyalkylene polyamines such as those of the formulae:

(i) NH₂-alkylene(O-alkylene)m NH₂ where m has a value of from 3 to 70, preferably 10 to 35; and

(ii) R-(alkylene(O-alkylene)n NH2)3-6 where each n has a value of about 1 to 40, with the proviso that the sum of all the n's is from 3 to 70 and preferably from 6 to 35, and R is a saturated hydrocarbon radical of up to ten carbon atoms, wherein the number of substituents on the R group is from 3 to 6. The alkylene groups in either formula (I) or (ii) may be straight or branched chains containing about 2 to 7, and preferably about 2 to 4, carbon atoms.

The polyoxyalkylene polyamines above, preferably polyoxyalkylene diamines and polyoxyalkylene triamines, may have average molecular weights ranging from 200 to 4,000 and preferably from 400 to 2,000. The preferred polyoxyalkylene polyamines include the polyoxyethylene and polyoxypropylene diamines and the polyoxypropylene triamines having average molecular weights ranging from 200 to 2,000. The polyoxyalkylene polyamines are commercially available and may be obtained, for example, from the Jefferson Chemical Company, Inc. under the trade name “Jeffamines D-230, D400, D-1000, D-2000, T-403,” etc.

The amine is readily reacted with the carboxylic acid material, e.g. alkenyl succinic anhydride, by heating an oil solution containing 5 to 95 weight percent of carboxylic acid material to from 100 to 250° C., preferably 125 to 175° C., generally for 1 to 10 hours, more preferably from 2 to 6 hours, until the desired amount of water has been removed. The heating is preferably carried out to favor formation of imides, or mixtures of imides and amides, rather than amides and salts. Reaction ratios can vary considerably, depending upon the reactants, amounts of excess amine, type of bonds formed, etc. Generally from 0.3 to 2 moles of amine, more preferably from 0.3 to 1.0 moles of amine, and even more preferably 0.4 to 0.8 mole of amine (e.g. bis-primary amine) is used per mole of the carboxylic acid moiety content (e.g. grafted maleic anhydride content). For example, one mole of olefin reacted with sufficient maleic anhydride to add 1.0 mole of maleic anhydride groups or mole of olefin when converted to a mixture of amides and imides, about 0.55 moles of amine with two primary groups would preferably be used, i.e. 0.50 mole of amine per mole of dicarboxylic acid moiety.

The nitrogen-containing dispersant can be further treated by boration as generally taught in U.S. Pat. Nos. 3,087,936 and 3,254,025, hereby incorporated by reference in their entirety.

Tris (hydroxymethyl) amino methane (THAM) can be reacted with the aforesaid acid material to form amides, imides or ester type additives as taught by GB-A-984 409, or to form oxazoline compounds and borated oxazoline compounds as described, for example, in U.S. Pat. Nos. 4,102,798, 4,116,876 and 4,113,639, hereby incorporated by reference in their entirety.

The ashless dispersants may also be esters derived from the long chain hydrocarbyl substituted carboxylic acid material and from hydroxy compounds such as monohydric and polyhydric alcohols or aromatic compounds such as phenols and naphthols, etc. The polyhydric alcohols are the most preferred hydroxy compound and preferably contain from 2 to 10 hydroxy radicals, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and other alkylene glycols in which the alkylene radical contains from 2 to 8 carbon atoms. Other useful polyhydric alcohols include glycerol, mono-oleate of glycerol, monostearate of glycerol, monomethyl ether of glycerol, pentaerythritol, dipentaerythritol, etc.

The ester dispersant may also be derived from unsaturated alcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexane-3-ol, and oleyl alcohol. Still other classes of alcohols capable of yielding the esters comprise the ether-alcohols and amino-alcohols including, for example the oxy-alkylene-, oxy-arylene-, amino-alkylene-, and amino-arylene-substituted alcohols having one or more oxy-alkylene, amino-alkylene or amino-arylene or amino-arylene oxy-arylene radicals. They are exemplified by Cellosolve, carbitol, N,N,N′,N′-tetrahydroxy-tri-methylene di-amine, and ether-alcohols having up to about 150 oxyalkylene radicals in which each alkylene radical contains from 1 to 8 carbon atoms.

The ester dispersant may be a di-ester of succinic acid or an acidic ester (i.e. a partially esterified succinic acid), or a partially esterified polyhydric alcohol or phenol, (i.e. an ester having free alcoholic or phenolic hydroxyl radicals). Mixtures of the above illustrated esters are likewise contemplated.

The ester dispersant may be prepared by one of several known methods as illustrated for example in U.S. Pat. No. 3,381,022, hereby incorporated by reference in their entirety.

Mannich base type dispersants such as those described in U.S. Pat. Nos. 3,649,229 and 3,798,165 (hereby incorporated by reference in their entirety) may also be used in these compositions. Such Mannich base dispersants can be formed by reacting a high molecular weight, hydrocarbyl-substituted mono- or polyhydroxyl benzene (e.g. having a number average molecular weight of 1,000 or greater) with amines (e.g. polyalkyl polyamines, polyalkenyl polyamines, aromatic amines, carboxylic acid-substituted polyamines and the succinimide formed from any one of these with an olefinic succinic acid or anhydride) and carbonyl compounds (e.g. formaldehyde or para formaldehyde).

A particularly suitable dispersant is one derived from polyisobutylene substituted with succinic anhydride groups and reacted with polyethylene amines, e.g. tetraethylene pentamine, pentaethylene hexamine, polyoxyethylene and polyoxypropylene amines, e.g. polyoxypropylene diamine, trismethylolaminomethane and pentaerythritol, and combinations thereof.

Detergents

Metal-containing rust inhibitors and/or detergents are frequently used with ashless dispersants. Such detergents and rust inhibitors include oil-soluble mono- and dicarboxylic acids, the metal salts of sulfonic acids, alkyl phenols, sulfurized alkyl phenols, alkyl salicylates and naphthenates in neutral or basic form. Highly basic (or “over-based”) metal salts, which are frequently used as detergents, appear particularly prone to promote oxidation of hydrocarbon oils containing them. Usually these metal-containing rust inhibitors and detergents are used in lubricating oil in amounts of from 0.01 to 10 weight percent, more preferably from 0.1 to 5 weight percent, based on the weight of the total lubricating composition.

Highly basic alkali metal and alkaline earth metal sulfonates are frequently used as detergents. They are usually produced by heating a mixture comprising an oil-soluble sulfonate or alkaryl sulfonic acid, with an excess of alkali metal or alkaline earth metal compound above that required for complete neutralization of any sulfonic acid present and thereafter forming a dispersed carbonate complex by reacting the excess metal with carbon dioxide to provide the desired overbasing. The sulfonic acids are typically obtained by the sulfonation of alkyl substituted aromatic hydrocarbons such as those obtained from the fractionation of petroleum by distillation and/or extraction or by the alkylation of aromatic hydrocarbons as for example those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl and the halogen derivatives such as chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation may be carried out in the presence of a catalyst with alkylating agents having from about 3 to more than 30 carbon atoms. For example, haloparaffins, olefins obtained by dehydrogenation of paraffins, polyolefin polymers produced from ethylene, propylene, etc. are all suitable. The alkaryl sulfonates usually contain from 9 to 70 or more carbon atoms, preferably from 16 to 50 carbon atoms per alkyl substituted aromatic moiety.

The alkali metal or alkaline earth metal compounds which may be used in neutralizing these alkaryl sulfonic acids to provide the sulfonates include the oxides and hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrosulfides, nitrates, borates and ethers of sodium, magnesium, calcium, strontium and barium. Non-limiting examples include calcium oxide, calcium hydroxide, magnesium oxide, magnesium acetate, and magnesium borate. As noted, the alkaline earth metal compound is used in excess of that required to complete neutralization of the alkaryl sulfonic acids. Generally, the amount ranges from 100 to 220 percent, although it is preferred to use at least 125 percent of the stoichiometric amount of metal required for complete neutralization.

Various other preparations of basic alkali metal and alkaline earth metal alkaryl sulfonates are known, such as those described in U.S. Pat. Nos. 3,150,088 and 3,150,089 (hereby incorporated by reference in their entirety) wherein overbasing is accomplished by hydrolysis of an alkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbon solvent-diluent oil.

Preferred alkaline earth sulfonate additives are magnesium alkyl aromatic sulfonate additives having a high total base number (TBN) as measured by ASTM 02896 of at least 250, more preferably ranging from 300 to 400, and calcium alkyl aromatic sulfonates having a TBN of at least 250, preferably from 300-400.

Neutral metal sulfonates are frequently used as rust inhibitors. Polyvalent metal alkyl salicylate and naphthenate materials are known additives for lubricating oil compositions to improve their high temperature performance and to counteract deposition of carbonaceous matter on pistons (e.g. U.S. Pat. No. 2,744,069, hereby incorporated by reference in their entirety). An increase in reserve basicity of the polyvalent metal alkyl salicylates and naphthenates can be realized by utilizing alkaline earth metal, e.g. calcium, salts of mixtures of C₈-C₂₆ alkyl salicylates and phenates (e.g. U.S. Pat. No. 2,744,069, hereby incorporated by reference in their entirety) or polyvalent metal salts of alkyl salicylic acids, said acids obtained from the alkylation of phenols followed by phenation, carboxylation and hydrolysis (e.g. U.S. Pat. No. 3,704,315, hereby incorporated by reference in their entirety) which could then be converted into highly basic salts by techniques generally known and used for such conversion. The reserve basicity of these metal-containing rust inhibitors is useful at TBN levels of between 60 and 150. Non-limiting examples of useful polyvalent metal salicylate and naphthenate materials are the methylene and sulfur bridged materials which are readily derived from alkyl substituted salicylic or naphthenic acids or mixtures of either or both with alkyl substituted phenols. Basic sulfurized salicylates and a method for their preparation are disclosed in U.S. Pat. No. 3,595,791, hereby incorporated by reference in their entirety. Such materials include alkaline earth metal, particularly magnesium, calcium, strontium and barium, salts of aromatic acids having the general formula:

HOOC—ArR³¹OH-Q_(k)(ArR³¹OH)r

where Ar is an aryl radical of 1 to 6 rings, R31 is an alkyl group having from 8 to 50 carbon atoms, preferably 12 to 30 carbon atoms (optimally about 12), Q is a sulfur (—S—) or methylene (—CH₂—) bridge, k is a number from 0 to 4 and r is a number from 0 to 4.

Preparation of the overbased Methylene Bridged Salicylate-Phenate Salt is readily carried out by conventional techniques such as by alkylation of a phenol followed by phenation, carboxylation, hydrolysis, methylene bridging a coupling agent such as an alkylene dihalide followed by salt formation concurrent with carbonation. An overbased calcium salt of a methylene bridged phenol-salicylic acid with a TBN of 60 to 150 is also useful.

Another type of basic metal detergent, the sulfurized metal phenates, can be considered a metal salt whether neutral or basic, of a compound typified by the general formula:

where j=1 or 2, q=0, 1 or 2 or a polymeric form of such a compound, where Rp is an alkyl radical, j and q are each integers from 1 to 4, and the average number of carbon atoms in all of the R groups is at least about 9 in order to ensure adequate solubility in oil. The individual R p groups may each contain from 5 to 40, preferably 8 to 20, carbon atoms. The metal salt is prepared by reacting an alkyl phenol sulfide with a sufficient quantity of metal containing material to impart the desired alkalinity to the sulfurized metal phenate.

Regardless of the manner in which they are prepared, the sulfurized alkyl phenols which are useful generally contain from 2 to 14 percent by weight, preferably 4 to 12 weight percent sulfur based on the weight of sulfurized alkyl phenol. The sulfurized alkyl phenol may be converted by reaction with a metal-containing material including oxides, hydroxides and complexes in an amount sufficient to neutralize said phenol and, if desired, to overbase the product to a desired alkalinity by procedures well known in the art. Preferred is a process of neutralization utilizing a solution of metal in glycol ether.

The neutral or normal sulfurized metal phenates are those in which the ratio of metal to phenol nucleus is about 1:2. The “overbased” or “basic” sulfurized metal phenates are sulfurized metal phenates wherein the ratio of metal to phenol is greater than the stoichiometric ratio, e.g. basic sulfurized metal dodecyl phenate has a metal content up to (or greater) than 100 percent in excess of the metal present in the corresponding normal sulfurized metal phenate. The excess metal is produced in oil-soluble or dispersible form (as by reaction with CO₂).

The detergents which may be included in the compositions of the present invention may optionally be borated in a known manner. Such boration provides the detergent with a measure of anti-wear activity.

It is preferred to use a combination of metal-containing detergents comprising calcium and magnesium salts or calcium, magnesium and sodium salts, as described above.

Antiwear Additives (Including Extreme Pressure Agents)

A wide variety of anti-wear additives may be included in the compositions or concentrates of the invention. For example, organic sulfides and polysulfides including especially dialkyl sulfides and polysulfides (e.g. dibutyl polysulfides, and dibenzyl sulfides and polysulfides) which may be substituted (e.g. with halogen, may be incorporated in the compositions or concentrates). Sulfurized esters, (e.g. sulfurized methyl or isopropyl oleate) and other sulfurized compounds, (e.g. sulfurized olefins such as sulfurized diisobutylene, sulfurized tripropylene or sulfurized dipentene) may also be added to the compositions. More complex sulfurized compounds such as sulfurized alkyl phenols and sulfurized terpenes and Diels-Alder adducts and sulfurized polymers, e.g. butadiene/butyl acrylate copolymers, may also be used, as may sulfurized tall oil fatty acid esters. Esters of beta-thiodipropionic acid, e.g. butyl, nonyl, tridecyl or eicosyl esters may also be used.

Anti-wear additives in the form of phosphorus esters, (e.g. di- and tri-alkyl, cycloalkyl or aryl phosphites) may also be used. Examples of such phosphites include dibutyl phosphite, dihexyl phosphite, dicyclohexyl phosphite, alkyl phenyl phosphites such as dimethylphenyl phosphite and mixed higher alkyl, (e.g. oleyl, alkyl phenyl phosphate, an example of which includes 4-pentyl phenyl phosphite). Phosphites based on polymers such as low molecular weight, polyethylenes and polypropylenes may also be used.

Preferred anti-wear additives for addition to the compositions and concentrates of the present invention are the dihydrocarbyl dithiophosphate metal salts. They also provide some antioxidant activity. The zinc salts are most commonly used in lubricating oils in amounts of 0.1 to 10, preferably 0.2 to 2, weight percent, based upon the total weight of the lubricating oil composition. Salts of other metals, e.g. barium and cadmium, can also be used. They may be prepared in accordance by first forming a dithiophosphoric acid, usually by reaction of an alcohol or a phenol with P2 S5 and then neutralizing the dithiophosphoric acid with a suitable zinc compound.

Alcohols may be used including mixtures of primary and secondary alcohols, with secondary alcohols generally for imparting improved antiwear properties, and primary alcohols forgiving improved thermal stability properties. Mixtures of the two are particularly useful. In general, any basic or neutral zinc compound could be used but the oxides, hydroxides and carbonates are most generally employed. Commercial additives frequently contain an excess of zinc due to use of an excess of the basic zinc compound in the neutralization reaction.

The zinc dihydrocarbyl dithiophosphates useful in the present invention are oil-soluble salts of dihydrocarbyl esters of dithiphosphoric acids and may be represented by the following formula

wherein A¹² and A¹³ may be the same or different hydrocarbyl radicals containing from 1 to 18, preferably 2 to 12, carbon atoms and including radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as A¹² and A¹³ groups are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals may, for example be ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, s-hexyl, i-hexyl, i-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, nonyl-phenyl, dodecyl-cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order to obtain oil solubility, the total number of carbon atoms in the dithiophosphoric acid (i.e. A¹² and A¹³) generally should be about 5 or greater and preferably 8 or greater.

Borated derivatives of the aforesaid antiwear agents may also be included in the compositions or concentrates of the invention.

Thiadiazole

The 1,3,4-thiadiazoles of formula I may be prepared by the method disclosed in U.S. Pat. Nos. 4,761,482 and 4,880,437, incorporated herein by reference in their entirety:

wherein T¹ and T² are independently selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, alkylthio, phenylalkyl, alkylated phenylalkyl, terpene residue and maleic acid residue of the formula

wherein R³² and R³³ are independently selected from the group consisting of hydrogen, branched or straight chain alkyl groups and cyclic aliphatic groups, wherein at least one of R³² and R³³ is not hydrogen.

An embodiment for the present invention includes alkyls which have from 1 to 50 carbon atoms which may be branched or straight chain and may be substituted with a hydroxyl group and an aryl group. Another embodiment for the present invention are T¹ and T² which are alkyl and alkylthio groups which contain 1 to 22 carbon atoms and may be branched or straight chain. Additional embodiments for the present invention include compounds wherein T¹ and T² together contain a total of at least 22 carbon atoms in their alkyl and/or alkylthio groups.

Embodiments of terpene residues for the present invention include terpenes which are derived from pinene and limonene.

An embodiment of maleic acid residues for the present invention include maleic acid residues where R³² and R³³ independently represents an alkyl group with 1 to 22 carbon atoms or C5-C7 cycloalkyl group. A further embodiment includes the total number of carbon atoms for R³² and R³³ combined being from 8 to 44 carbon atoms.

Commercially available thiadiazoles derivatives are VANLUBE® 871 (butanedioic acid ((4,5-dihydro-5-thioxo-1,3,4-thiadiazol-2-yl) thio-bis(2-ethylhexyl) ester) CUVAN® 826 (2,5-dimercapto-1,3,4-thiadiazole) and CUVAN® 484 (alkylthiadiazole) manufactured by R. T. Vanderbilt Company, Hitec™ 4313, 4312, RC 8210, and RC 8213.

Dithiocarbamates (i) Bisdithiocarbamates

The bisdithiocarbamates of formula are known compounds described in U.S. Pat. No. 4,648,985, incorporated herein by reference in its entirety.

The compounds are characterized by R³⁴, R³⁵, R³⁶ and R³⁷ which are the same or different and are hydrocarbyl groups having 1 to 13 carbon atoms.

Embodiments for the present invention include bisdithiocarbamates wherein R³⁴, R³⁵, R³⁶ and R³⁷ are the same or different and are branched or straight chain alkyl groups having 1 to 8 carbon atoms.

R³⁸ is an aliphatic group such as straight and branched alkylene groups containing 1 to 8 carbons. An embodiment for R³⁸ is methylenebis (dibutyldithiocarbamate) available commercially from R. T. Vanderbilt Company, Inc. under the tradename VANLUBE® 7723, and from King Industries under the tradename NA-LUBE® ADTC.

(ii) Ashless Dithiocarbamate Esters

The compounds of the above formula are characterized by groups R³⁹, R⁴⁰, R⁴¹ and R⁴² which are the same or different and are hydrocarbyl groups having 1 to 13 carbon atoms. VANLUBE® 732 and VANLUBE.® 981 are commercially available from R. T. Vanderbilt Company, Inc.

(iii) Metal Dithiocarbamates

The dithiocarbamates of the above formula are known compounds. One of the processes of preparation is disclosed in U.S. Pat. No. 2,492,314, which is hereby incorporated by reference in its entirety. R^(d) and R^(e) represent branched or straight chain alkyl groups having 1 to 8 carbon atoms, M is a metal cation and n is an integer based upon the valency of the metal cation (e.g. n=1 for sodium (Na⁺); n=2 for zinc (Zn⁺⁺); etc.). Molybdenum dithiocarbamate processes are described in U.S. Pat. Nos. 3,356,702; 4,098,705; and 5,627,146, each of which is hereby incorporated by reference. Substitution is described as branched or straight chain ranging from 8 to 13 carbon atoms in each alkyl group.

Embodiments for the present invention include metal dithiocarbamates which are antimony, zinc and tungsten dithiocarbamates.

Additionally the lubricant composition may also include phosphorous dithiophosphate compounds. Embodiments of dithiophosphates for the present invention include:

(i) Metal Phosphorodithioates

The metal phosphorodithioates are known, commercially available materials. One of the processes of preparation is taught by U.S. Pat. No. 4,215,067, which is hereby incorporated by reference in its entirety. (M and n are as defined above for the metal dithiocarbamates) R^(f) and R^(g) represent branched and straight chain alkyl groups having 1-22 groups and may be derived from fatty acids. In one embodiment the metal phosphorodithioates are zinc phosphorodithioates. The metal ion in formula V may be selected from the following groups of the Periodic Table: IIA, IIIA, VA, VIA, IB, IIB, VIB and VIII. Amine salts of the compounds are also useful synergists of the invention. Embodiments of such amine salts include those prepared from alkyl amines and mixed alkyl amines. An additional embodiment includes amine salts based on fatty acid amines.

(ii) Phosphorodithioate Esters

The phosphorodithioate esters are known compounds. One of the processes of manufacture is disclosed in U.S. Pat. No. 3,567,638, which is hereby incorporated by reference in its entirety. R^(j), R^(k), R^(l) and R^(m) may be the same or different and may be branched and straight chain alkyl groups. Embodiments for the present invention include branched or straight chain alkyl groups containing 1 to 8 carbon atoms.

Embodiments for the ranges of phosphorodithioate (also known as dithiophosphate) compound, or mixture of dithiophosphate compounds, are 0.05-2.00%; 0.5-1.50%; and 0.5-0.8% (each percentage being percent by weight based upon the total weight of the composition).

Additional Antioxidants

Additional antioxidants which are especially useful in lubricating oil compositions or concentrates are based on oil-soluble copper compounds, e.g. in the form of a synthetic or natural carboxylic acid salt. By “oil-soluble” is meant that the compound is oil-soluble or solubilized under normal blending conditions in the oil or concentrate. Examples of oil-soluble copper compounds include salts of C₁₀ to C₁₈ fatty acids such as stearic or palmitic acid; but unsaturated acids (such as oleic acid), branched carboxylic acids (such as naphthenic acids) of molecular weight from 200 to 500, dicarboxylic acids such as polyisobutenyl succinic acids, and synthetic carboxylic acids can all be used because of the acceptable handling and solubility properties of the resulting copper carboxylates.

Suitable oil-soluble copper dithiocarbamates have the general formula

where p is 1 or 2 and R44 and R45 may be the same or different hydrocarbyl radicals containing from 1 to 18 carbon atoms each and including radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R⁴⁴ and R⁴⁵ groups are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals may be, for example, ethyl, n-propyl, n-butyl, i-butyl, sec-butyl, amyl, sec-hexyl, i-hexyl, i-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, nonyl-phenyl, dodecyl-phenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order to obtain oil solubility, the total number of carbon atoms (i.e. R⁴⁴ and R⁴⁵) generally should be about 5 or greater.

Copper salts of dithiophosphonic acids (the acid as described hereinbefore in relation to antiwear additives specifically as zinc salts), copper sulfonates, phenates, copper polyisobutylene succinic anhydride (“Copper PIBSA”) carboxylates such as oleates, stearates and mixtures thereof, and acetyl acetonates can also be used.

These antioxidants can be used in amounts such that, in the final lubricating composition, a copper concentration of from 5 to 500 ppm is present.

Other known oil-soluble or oil-ispersible, and preferably liquid, antioxidants may also be used in the compositions of the invention. Examples of such antioxidants include hindered phenols, which may contain sulphur, e.g. 4,4′-methylene bis(2,6-di(t-butyl)phenol), 4,4′-thio bis(2,6-di(t-butyl)phenol) and p-alkylated hindered phenols; unhindered phenols which again may contain sulphur such as 2,2′-thio bis-(4-nonyl phenol) and 2,2′-methylene bis(4-nonylphenol); phenothiazine derivatives, e.g. those containing higher alkyl substituents such as dioctyl and dinonyl phenothiazines; substituted alpha and betanaphthyl amines such as phenyl beta-naphthylamine and its alkylated derivatives; other amino aryl compounds such as for example 4, 4′-bis(secbutylamino) diphenylmethane; dithiocarbamates such as zinc, nickel, copper, or molybdenum dithiocarbamates; and phosphosulfurized olefins, e.g. phosphosulfurized pinene or styrene.

Corrosion Inhibitors and Metal Deactivators

Corrosion inhibitors which act by deactivating metal parts with which they come in contact and/or as sulfur scavengers can also be used in the compositions or concentrates of the invention. Examples of such agents include benzotriazole derivatives; thiadiazole compounds, e.g. 2,5-dimercapto 1,3,4-thiadiazole; mercaptobenzothiazole compounds in the form of amine salts, sulphonamides, thiosulphonamides, and condensates of mercaptobenzothiazole with amines and formaldehyde; salicylaldehyde/diamine condensation products; dialkylphosphites, e.g. dioleyl or di-2-ethylhexyl phosphite; trialkyl and triarylphosphites, e.g. tris-(2-ethyl-hexyl), triphenyl or tri(4-nonylphenol) phosphites; and thiophosphonates such as triphenyl or trilauryl thiophosphonate or trilauryl tetrathiophosphonate.

Also useful are corrosion inhibitors based on aromatic sulfonic acid derivatives, for example derivative of a mono-, di-, or poly-alkylated naphthalenesulfonic acid selected from the group consisting of:

(i) neutral metal salts of said mono-, di-, and poly-alkylated naphthalenesulfonic acids;

(ii) basic metal salts of said mono-, di-, and poly-alkylated naphthalenesulfonic acids;

(iii) amine salts of said mono-, di-, and poly-alkylated naphthalenesulfonic acids; and

(iv) esters of said mono-, di-, and poly-alkylated naphthalenesulfonic acids; wherein the mono-, di-, and poly-alkylated naphthalenesulfonic acids are represented by formula

wherein R₅₁, R₅₂, R₅₃ and R₅₄ are individually selected from the group consisting of hydrogen or essentially linear hydrocarbyl groups having about 9 to about 22 carbon atoms; and wherein l, m, n and p are integers from 0 to 4 and the sum of l+m+n+p is at least 1; and wherein R₅₁, R₅₂, R₅₃ and R₅₄ is a hydrogen where either l, m, n, or p is 0.

One derivative of the alkylated naphthalenesulfonic acid composition is the neutral metal salt component and is represented by the formula (II):

wherein R₅₁, R₅₂, R₅₃ and R₅₄, l, m, n and p are as defined above; M is a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Group IVb metals, and Group Vb metals; and x is the valence of M. M in formula (II) is an alkali metal selected from the group consisting of lithium, sodium, potassium, and mixtures thereof. M may also be an alkaline earth metal selected from the group consisting of magnesium, calcium, strontium, barium and mixtures thereof. In other embodiments, M is a transition metal selected from the group consisting of zinc, copper, cerium, molybdenum, and mixtures thereof. In still other embodiments M may be a Group IVb metal and selected from the group consisting of tin, lead, and mixtures thereof M may be a Group Vb metal selected from the group consisting of bismuth, antimony, and mixtures thereof.

The functional fluid composition may also contain at least one derivative of the alkylated naphthalenesulfonic acid composition that is the overbased metal salt component described above and represented by formulae

and mixtures thereof wherein R₅₁, R₅₂, R₅₃ and R₅₄, l, m, n and p are as defined earlier; M is a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Group IVb metals, and Group Vb metals; x is the valence of M; and z is 0.1 to 50.

The functional fluid composition contains one ammonium or organic amine salt of formulae

wherein R₅₁, R₅₂, R₅₃ and R₅₄, l, m, n and p are as defined earlier and each R₅₅ is individually selected from a hydrogen atom or a hydrocarbyl group consisting of from 1 to 25 carbon atoms; and x is from 2 to 5.

The functional fluid composition contains at least one compound represented by formula

wherein R₅₁, R₅₂, R₅₃ and R₅₄, l, m, n and p are as defined earlier and R₅₆ is a hydrocarbyl group consisting of from 2 to 18 carbon atoms.

Also useful are corrosion inhibitors based on N-acyl-N-hydrocarbonoxyalkyl aspartic acid compounds having the formula

wherein R⁶¹ is a hydrocarbonoxyalkyl group of from about 6 to about 30 carbon atoms, R⁶² is a carboxyl substituted acyl group containing from about 2 to about 30 carbon atoms, or such a group at least partially neutralized with an alkali metal base, an alkaline earth metal base, an amine or a mixture of any of the foregoing, and R⁶⁴, R⁶¹, R⁶⁶, and R⁶⁷ are each, independently, selected from hydrogen or a hydrocarbon group of from about 1 to about 30 carbon atoms.

Friction Modifiers and Fuel Economy Agents

Friction modifiers and fuel economy agents, compatible with the other ingredients of the new compositions or concentrates may also be included. Examples of such materials are glyceryl monoesters and/or diesters of higher fatty acids, e.g. glyceryl mono-oleate and esters of long-chain polycarboxylic acids with diols, e.g. the butane diol ester of a dimerized unsaturated fatty acid, and oxazoline compounds.

Succinimides

Succinimides friction modifiers of the current invention may be represented by the following general formula.

where R18 is a C6 to C30 isomerized alkenyl group, represented by:

(where g and h are integers whose sum is from 1 to 25), or its fully saturated alkyl analog, R17 is an alkyl group, aryl group, and their heteroatom containing derivatives.

The succinimides of the present invention are those produced from succinic anhydrides substituted with isomerized alkenyl groups or their fully saturated alkyl analogs. Preparation of the Isomerized Alkenyl Succinic Anhydrides is Described in, for Example, U.S. Pat. No. 3,382,172 hereby incorporated by reference in its entirety.

Often these materials are prepared by heating alpha-olefins with acidic catalysts to migrate the double bond to form an internalolefin. This mixture of olefins (2-enes, 3-enes, etc.) is then thermally reacted with maleic anhydride. Typically olefins from C₆ (e.g. 1-hexene) to C₃₀ (e.g. 1-tricosane) are used. Suitable isomerized alkenyl succinic anhydrides of structure (1)

include isodecylsuccinic anhydride (x+y=5), iso-dodecylsuccinic anhydride (x+y=7), iso-tetradecylsuccinic anhydride (x+y=9), iso-hexadecylsuccinic anhydride (x+y=11), iso-octadecylsuccinic anhydride (x+y=13) and isoeicosylsuccinic anhydride (x+y=15). Preferred materials are isohexadecylsuccinic anhydride and iso-octadecylsuccinic anhydride.

The materials produced by this process contain one double bond (alkenyl group) in the alkyl chain. The alkenyl substituted succinic anhydrides may be easily converted to their saturated alkyl analogs by hydrogenation.

Suitable primary and secondary amines useful to produce the succinimides are represented by structure

where: R¹⁹ and R²⁰ are independently alkyl, aryl, their heteroatom containing derivatives, or H with the proviso that R¹⁹ and R²⁰ are not both H. Preferred amines are n-hexylamine, di-n-hexylamine, dimethylamine, n-butylamine, diethanol amine and di-methyiaminopropylamine.

Bis succinimides of the current invention may be represented by the following general formula

wherein R²¹ and R²² may be identical or different from each other and are each hydrocarbon groups having 5 or more carbons; R²³ is a divalent hydrocarbon group having 1 to 5 carbons; R²⁴ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbons; and n is an integer in the range of 0 to 10

In the above general formula, R²¹ and R²² may be the same as each other or different from each other, and are each saturated or unsaturated hydrocarbon groups having 5 or more carbons, preferably 5 to 40 carbons. Examples of hydrocarbon groups include pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, hexadecyl groups, heptadecyl groups, octadecyl groups, nonadecyl groups, oleyl groups and other hydrocarbon groups having up to 40 carbons. Preferred hydrocarbon groups include straight chain hydrocarbon groups having between 8 and 25 carbons. In the above general formula, R²³ is a divalent hydrocarbon group having 1 to 5 carbons, preferably an alkylene group having 2 or 3 carbons.

In the above general formula, R²⁴ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbons. Examples of hydrocarbon groups include alkyl groups having 1 to 20 carbons; alkenyl groups having 2 to 20 carbons; cycloalkyl groups having 6 to 20 carbons; and aryl groups having 6 to 20 carbons. The aryl groups may have an alkyl group having 1 to 12 carbons. Hydrogen atoms and alkyl groups having 1 to 10 carbons are particularly preferred as R²⁴. Groups having a number of amino groups and/or amide bonds in their structure (e.g. 1 to 5 of each) can be used as the above-described hydrocarbon groups.

The amino groups are represented by —NH— or —NH₂; and the amide bonds are represented by

They may be bonded with the carbons of the hydrocarbon group at an arbitrary position.

The bis succinimides of the present invention are those produced from succinic anhydrides substituted with isomerized alkenyl groups or their fully saturated alkyl analogs, and polyamines. Suitable polyamines are saturated amines of the general formula

where R²⁵, R²⁶, and R²⁷ are independently selected from the group consisting of H, C₁ to C₂₅ straight or branched chain alkyl radicals, C₁ to C₁₂ alkoxy radicals; C₂ to C₆ alkylene radicals; u is an integer from 1 to 6, preferably 2 to 4; and v is an integer from 0 to 10, preferably from 1 to 4.

Non-limiting examples of suitable polyamine compounds include: 1,6-diaminohexane, diethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene hexamine. Useful mixtures of polyamines having from 5 to 7 nitrogen atoms per molecule are available from Dow Chemical Co. as Polyamine H, Polyamine 400 and Polyamine E-300.

Polyoxyalkylene amines are also useful in this invention and are shown as structure

H₂N-alkylene-(—O-alkylene-)u₁-NH₂

where u₁ is an integer of from 1 to 10. The polyamines have molecular weights from about 100 to 500. The preferred polyoxyalkylene polyamines include polyoxyethylene and polyoxypropylene diamines and the polyoxypropylene triamines. Commercial polyoxyalkylene amines are available from Jefferson Chemical Co. sold under the trade name “Jeffamines® D-230, D-400, D-1 000, T-430,” etc.

In preferred embodiments, the alkenyl succinic anhydride starting materials for forming the friction modifiers of above structure can be either of two types. The two types differ in the linkage of the alkyl side chain to the succinic acid moiety. In the first type, the alkyl group is joined through a primary carbon atom in the starting olefin, and therefore the carbon atom adjacent to the succinic acid moiety is a secondary carbon atom. In the second type, the linkage is made through a secondary carbon atom in the starting olefin and these materials accordingly have a branched or isomerized side chain. The carbon atom adjacent to the succinic acid moiety therefore is necessarily a tertiary carbon atom.

The alkenyl succinic anhydrides of the first type, shown below, with linkages through secondary carbon atoms, are prepared simply by heating α-olefins, that is, terminally unsaturated olefins, with maleic anhydride. Non-limiting examples of these materials include n-decenyl succinic anhydride, tetradecenyl succinic anhydride, n-octadecenyl succinic anhydride, tetrapropenyl succinic anhydride, poly butenyl succinic anhydrides, etc.

wherein R⁷⁸ is C₂ to C₃₇ alkyl.

A second type of alkenyl succinic anhydrides, with linkage through tertiary carbon atoms, is produced from internally unsaturated olefins and maleic anhydride. Internal olefins are olefins which are not terminally unsaturated, and therefore do not contain the

moiety. These internal olefins can be introduced into the reaction mixture as such, or they can be produced in situ by exposing α-olefins to isomerization catalysts at high temperatures. A process for producing such materials is described in U.S. Pat. No. 3,382,172 hereby incorporated by reference in its entirety. The isomerized alkenyl substituted succinic anhydrides are compounds having structure

where x and y are independent integers whose sum is from 1 to 35.

The preferred succinic anhydrides are produced from isomerization of linear α-olefins with an acidic catalyst followed by reaction with maleic anhydride. The preferred α-olefins are 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosane, or mixtures of these materials. The products described can also be produced from internal olefins of the same carbon numbers, 8 to 20. The preferred materials for this invention are those made from 1-tetradecene (x+y=9), 1-hexadecene (x+y=11), 1-octadecene (x+y=13), 1-didodecene (x+y=15), and 1-tetradidodecene (x+y=19) or mixtures thereof.

The preferred succinimide friction modifiers of this invention are products produced by the reaction of isomerized alkenyl succinic anhydride with diethylene triamine, triethylene tetramine, tetraethylene pentamine or mixtures thereof. The most preferred products are prepared using diethylene triamine, triethylene tetramine, and tetraethylene pentamine. The alkenyl succinic anhydrides are typically reacted with the amines in a 2:1 molar ratio so that both primary amines are converted to succinimides. Sometimes a slight excess of isomerized alkenyl succinic anhydride is used to insure that all primary amines have reacted.

The two types of succinimide friction modifiers can be used individually or in combination.

The disuccinimides may be post-treated or further processed by any number of techniques known in the art. These techniques would include, but are not limited to, boration, maleation, and acid treating with inorganic acids such as phosphoric acid, phosphorous acid, and sulfuric acid. Descriptions of these processes can be found in, for example, U.S. Pat. Nos. 3,254,025; 3,502,677; 4,686,054; and 4,857,214 hereby incorporated by reference in their entirety.

Other useful derivatives of the succinimide modifiers are where the alkenyl groups of above structures have been hydrogenated to form their saturated alkyl analogs. Saturation of the condensation products of olefins and maleic anhydride may be accomplished before or after reaction with the amine. These saturated versions of above structures may likewise be post-treated as previously described.

While any effective amount of the compounds of above structure and its derivatives may be used to achieve the benefits of this invention, typically these effective amounts will range from 0.01 to 10 weight percent of the finished fluid, preferably from 0.05 to 7 weight percent, most preferably from 0.1 to 5 weight percent.

Viscosity Index Improvers

Viscosity index improvers or viscosity modifiers are typically polymers of number average molecular weight 103 to 106—for example ethylene copolymers or polybutenes. Viscosity index improvers may be modified to have dispersant properties and suitable viscosity index improver dispersants for use in compositions of the invention are described in, for example, EP 24 146 A and are as follows:

(a) polymers comprising monomer units derived from a C₄ to C₂₄ unsaturated ester of vinyl alcohol or a C₃ to C₁₀ unsaturated mono- or dicarboxylic acid and an unsaturated nitrogen-containing monomer having 4 to 20 carbon atoms;

(b) polymers comprising monomer units derived from a C₄ to C₂₀ olefin and an unsaturated C₃ to C₁₀ mono- or dicarboxylic acid neutralized with an amine, a hydroxyamine or an alcohol; and

(c) polymers of ethylene with a C₃ to C₂₀ olefin further reacted by grafting a C₄ to C₂₀ nitrogen-containing monomer thereon or by grafting an unsaturated acid onto the polymer backbone and then reacting the carboxylic acid groups with an amine, hydroxy amine, or alcohol. (Other additives which may be used in accordance with the present invention are described in EP24146A). These viscosity index improvers also have dispersant properties, as is preferred in accordance with the invention, although viscosity index improvers without dispersant properties may be used if desired.

Preferred viscosity index improvers with dispersant properties for use in the compositions of the present invention comprise a polyolefin moiety to which is grafted an unsaturated carboxylic acid moiety, the carboxylic acid groups being reacted with an amine, hydroxyamine or alcohol.

Antioxidants may be evaluated using the sequence III E test (ASTM STP 315) which is a standard test used for assessing the oxidation resistance of lubricants and which is a more stringent version of the sequence III D test (ASTM STP 315M and ASTM STP 315). The sequence III method produces a result after 64 hrs of testing with an acceptable performance being a 375% or less increase in kinematic viscosity as measured at 40° C. after this period. The principle of this method is to observe oil thickening as a result of oxidation. When evaluating antioxidants for lubricants it is desirable to be able to use screening test methods which are quicker and easier to use than the Sequence III test. One such method which is commonly used is a thin film high temperature catalytic oxidation test performed using a DSC.

Synergistic Relationships Between Amine Tungstates and Lubricant Additives

Applicants have found a surprising synergistic interaction of the amine tungstates of the invention with various lubricant additives, described herein. The synergistic interaction is evidenced by enhanced performance properties of a lubricating oil composition of the invention compared to the analogous lubricating oil composition both without the amine tungstates and without the lubricant additive.

The enhanced properties that demonstrate the synergistic interaction of the invention include but are not limited to oxidative stability, antiwear, extreme pressure, and anti-friction performance.

A first embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more ashless friction modifier. Ashless friction modifiers of this first embodiment include, but are not limited to succinimide dispersants, borates succinimide dispersants, glycerol monooleate, cocoamide DEA, long chain fatty amines, and long chain fatty esters. The synergistic interaction of the first embodiment may be demonstrated by any analytical test including, but not limited to Optimol SRV (ASTM D 5707 Method).

A second embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more metal-containing antiwear additive. Metal-containing antiwear additives of this second embodiment include, but are not limited to, molybdenum dialkyldithiocarbamates, molybdenum dialkyldithiophosphates, and zinc dialkyldithiophosphates. The synergistic interaction of the first embodiment may be demonstrated by any analytical test including, but not limited to ASTM D 2272 Rotory Pressure Vessel Oxidation Test and ASTM D 4172 4-Ball Wear Test.

A third embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more ashless antiwear additive. Ashless antiwear additives of this third embodiment include, but are not limited to, amine dithiocarbamates, ashless dithiophosphates, ashless phosphates, ashless phosphites, ashless trialkylthiophosphates, and ashless triarylthiophosphates. The synergistic interaction of the third embodiment may be demonstrated by any analytical test including, but not limited to ASTM D 4172 4-Ball Wear Test.

A fourth embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more extreme pressure agent. Extreme pressure agents of this fourth embodiment include, but are not limited to, sulfurized olefins and sulfurized esters. The synergistic interaction of the fourth embodiment may be demonstrated by any analytical test including, but not limited to ASTM D 2783 4-Ball Weld Extreme Pressure Test.

A fifth embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more corrosion inhibitor/detergent. Corrosion inhibitors/detergents of this fifth embodiment include, but are not limited to, metallic sulfonates (including “overbased” metal sulfonates containing high total base number), ashless sulfonates, metallic salicylates, organic amine carboxylates. The synergistic interaction of the fifth embodiment may be demonstrated by any analytical test including, but not limited to, ASTM D-665B Rust Test, ASTM D 2783 4-Ball Weld Extreme Pressure Test, and Optimol SRV (ASTM D 5705 Method).

A sixth embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more yellow metal deactivator/copper passivating agent. Yellow metal deactivators/copper passivating agents of this sixth embodiment include, but are not limited tobenzotriazole, tolyltriazole and dimercaptothiadiazole derivatives. The synergistic interaction of the sixth embodiment may be demonstrated by any analytical test including, but not limited to, Optimol SRV (ASTM D 5707 Method) and ASTM D 130 Copper Strip Corrosion Test.

A seventh embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more viscosity index improvers. Viscosity index improvers of this seventh embodiment include, but are not limited to, olefin copolymers (OCPs), olefin/diene copolymers such as styrene divinylbenzene copolymers, polyacrylates and graft olefin copolymers containing amine and/or carboxylic acid functional groups. The synergistic interaction of the seventh embodiment may be demonstrated by any analytical test including, but not limited to, Optimol SRV (ASTM D 5707 Method), ASTM D 7342 Shear Stability Test and viscosity index measurement.

An eighth embodiment of the invention that demonstrates the synergistic effect is a lubricating oil composition comprising a lubricating oil, an organo amine tungstate, a secondary diarylamine and/or alkylated phenothiazine, and further comprising one or more pour point depressants. Pour point depressants of this eighth embodiment include, but are not limited to, polyacrylates and poly(alkylaromatics). The synergistic interaction of the eighth embodiment may be demonstrated by any analytical test including, but not limited to, Optimol SRV (ASTM D 5707 Method), ASTM D 4172 4-Ball Wear Test and ASTM D 97 Pour Point Test.

Other examples of friction modifiers suitable for use in the present invention include substituted succinimides such as glycolated or borated succinimide friction modifiers. Also useful are such compounds as aliphatic fatty amines or alkoxylated aliphatic fatty amines, alkoxylated aliphatic ether amines, aliphatic carboxylic acids, aliphatic fatty acid amides, alkoxylated aliphatic fatty acid amides, aliphatic fatty imidazolines, and aliphatic fatty tertiary amines, wherein the aliphatic group usually contains above about eight carbon atoms so as to render the compound suitably oil soluble. Also useful are aliphatic substituted succinimides formed by reacting one or more aliphatic succinic acids or anhydrides with ammonia or other primary amines such as those taught in EP-A-0389237, as well as mixtures of two or more friction modifiers. Friction modifiers suitable for use in the present invention are described in the following U.S. patents, incorporated herein by reference for their disclosures relating to friction modifiers: U.S. Pat. Nos. 5,344,579; 5,372,735 and 5,441,656.

In addition, other types of ashless friction modifiers can include

(i) fatty phosphites (ii) fatty acid amides (iii) fatty epoxides (iv) borated fatty epoxides (v) fatty amines other than component (b) above (vi) glycerol esters (vii) borated glycerol esters (viii) alkoxylated fatty amines (ix) borated alkoxylated fatty amines (x) metal salts of fatty acids (xi) sulfurized olefins (xii) fatty imidazolines (xiii) condensation products of carboxylic acids and polyalkylene-polyamines (xv) amine salts of alkylphosphoric acids and mixtures thereof.

Representatives of each of these types of friction modifiers are known and are commercially available. For instance, (i) fatty phosphites are generally of the formula (RO)₂PHO. The preferred dialkyl phosphite, as shown in the preceding formula, is typically present with a minor amount of monoalkyl phosphite of the formula (RO)(HO)PHO. In these structures, the term “R” is conventionally referred to as an alkyl group. The terms “alkyl” and “alkylated,” as used herein, will embrace both saturated and unsaturated alkyl groups within the phosphite. The phosphite should have sufficient hydrocarbyl groups to render the phosphite substantially oleophilic. Preferably the hydrocarbyl groups are substantially unbranched. Many suitable phosphites are available commercially and may be synthesized as described in U.S. Pat. No. 4,752,416. It is preferred that the phosphite contain 8 to 24 carbon atoms in each of R groups. Preferably, the fatty phosphite contains 12 to 22 carbon atoms in each of the fatty radicals, most preferably 16 to 20 carbon atoms. In one embodiment the fatty phosphite can be formed from oleyl groups, thus having 18 carbon atoms in each fatty radical.

(iv) Borated fatty epoxides are known from Canadian Patent No. 1,188,704. These oil-soluble boron-containing compositions are prepared by reacting, at a temperature from 80° C. to 250° C., boric acid or boron trioxide with at least one fatty epoxide having the formula wherein each of R₁, R₂, R₃ and R₄ is hydrogen or an aliphatic radical, or any two thereof together with the epoxy carbon atom or atoms to which they are attached, form a cyclic radical. The fatty epoxide preferably contains at least 8 carbon atoms.

The borated fatty epoxides can be characterized by the method for their preparation which involves the reaction of two materials. Reagent A can be boron trioxide or any of the various forms of boric acid including metaboric acid (HBO₂), orthoboric acid (H₃BO₃) and tetraboric acid (H₂B₄O₇). Boric acid, and especially orthoboric acid, is preferred. Reagent B can be at least one fatty epoxide having the above formula. In the formula, each of the R groups is most often hydrogen or an aliphatic radical with at least one being a hydrocarbyl or aliphatic radical containing at least 6 carbon atoms. The molar ratio of reagent A to reagent B is generally 1:0.25 to 1:4. Ratios of 1:1 to 1:3 are preferred, with about 1:2 being an especially preferred ratio. The borated fatty epoxides can be prepared by merely blending the two reagents and heating them at temperature of 80.degree. to 250° C., preferably 100° to 200° C., for a period of time sufficient for reaction to take place. If desired, the reaction may be effected in the presence of a substantially inert, normally liquid organic diluent. During the reaction, water is evolved and may be removed by distillation.

(iii) Non-borated fatty epoxides, corresponding to “Reagent B” above, are also useful as friction modifiers.

Borated amines are generally known from U.S. Pat. No. 4,622,158. Borated amine friction modifiers (including (ix) borated alkoxylated fatty amines) are conveniently prepared by the reaction of a boron compounds, as described above, with the corresponding amines. The amine can be a simple fatty amine or hydroxy containing tertiary amines. The borated amines can be prepared by adding the boron reactant, as described above, to an amine reactant and heating the resulting mixture at a 500 to 300° C., preferably 100° C. to 250° C. or 150. ° C. to 230° C., with stirring. The reaction is continued until by-product water ceases to evolve from the reaction mixture indicating completion of the reaction.

Among the amines useful in preparing the borated amines are commercial alkoxylated fatty amines known by the trademark “ETHOMEEN” and available from Akzo Nobel. Representative examples of these ETHOMEEN.™. materials is ETHOMEEN.™. C/12 (bis[2-hydroxyethyl]-coco-amine); ETHOMEEN.™. C/20 (polyoxyethylene[10]cocoamine); ETHOMEEN.™. S/12 (bis[2-hydroxyethyl]soyamine); ETHOMEEN.™. T/12 (bis[2-hydroxyethyl]-tallow-amine); ETHOMEEN.™. T/15 (polyoxyethylene-[5]tallowamine); ETHOMEEN.™. 0/12 (bis[2-hydroxyethyl]oleyl-amine); ETHOMEEN.™. 18/12 (bis[2-hydroxyethyl]octadecylamine); and ETHOMEEN.™. 18/25 (poly-oxyethyl-ene[15]octadecylamine). Fatty amines and ethoxylated fatty amines are also described in U.S. Pat. No. 4,741,848.

The (viii) alkoxylated fatty amines, and (v) fatty amines themselves (such as oleylamine) are useful as friction modifiers in this invention. Such amines are commercially available.

Both borated and unborated fatty acid esters of glycerol can be used as friction modifiers. The (vii) borated fatty acid esters of glycerol are prepared by borating a fatty acid ester of glycerol with boric acid with removal of the water of reaction. Preferably, there is sufficient boron present such that each boron will react with from 1.5 to 2.5 hydroxyl groups present in the reaction mixture. The reaction may be carried out at a temperature in the range of 60° C. to 135° C., in the absence or presence of any suitable organic solvent such as methanol, benzene, xylenes, toluene, or oil.

(vi) Fatty acid esters of glycerol themselves can be prepared by a variety of methods well known in the art. Many of these esters, such as glycerol monooleate and glycerol tallowate, are manufactured on a commercial scale. The esters useful are oil-soluble and are preferably prepared from C8 to C22 fatty acids or mixtures thereof such as are found in natural products and as are described in greater detail below. Fatty acid monoesters of glycerol are preferred, although, mixtures of mono- and diesters may be used. For example, commercial glycerol monooleate may contain a mixture of 45% to 55% by weight monoester and 55% to 45% diester.

Fatty acids can be used in preparing the above glycerol esters; they can also be used in preparing their (x) metal salts, (ii) amides, and (xii) imidazolines, any of which can also be used as friction modifiers. Preferred fatty acids are those containing 6 to 24 carbon atoms, preferably 8 to 18. The acids can be branched or straight-chain, saturated or unsaturated. Suitable acids include 2-ethylhexanoic, decanoic, oleic, stearic, isostearic, palmitic, myristic, palmitoleic, linoleic, lauric, and linolenic acids, and the acids from the natural products tallow, palm oil, olive oil, peanut oil, corn oil, and Neat's foot oil. A particularly preferred acid is oleic acid. Preferred metal salts include zinc and calcium salts. Examples are overbased calcium salts and basic oleic acid-zinc salt complexes which can be represented by the general formula Zn4Oleate₃O₁. Preferred amides are those prepared by condensation with ammonia or with primary or secondary amines such as diethylamine and diethanolamine. Fatty imidazolines are the cyclic condensation product of an acid with a diamine or polyamine such as a polyethylenepolyamine.

Sulfurized olefins (xi) are well known commercial materials used as friction modifiers. A particularly preferred sulfurized olefin is one which is prepared in accordance with the detailed teachings of U.S. Pat. Nos. 4,957,651 and 4,959,168. Described therein is a cosulfurized mixture of 2 or more reactants selected from the group consisting of (1) at least one fatty acid ester of a polyhydric alcohol, (2) at least one fatty acid, (3) at least one olefin, and (4) at least one fatty acid ester of a monohydric alcohol.

Reactant (3), the olefin component, comprises at least one olefin. This olefin is preferably an aliphatic olefin, which usually will contain 4 to 40 carbon atoms, preferably from 8 to 36 carbon atoms. Terminal olefins, or alpha-olefins, are preferred, especially those having from 12 to 20 carbon atoms. Mixtures of these olefins are commercially available, and such mixtures are contemplated for use in this invention.

The cosulfurized mixture of two or more of the reactants, is prepared by reacting the mixture of appropriate reactants with a source of sulfur. The mixture to be sulfurized can contain 10 to 90 parts of Reactant (1), or 0.1 15 parts by weight of Reactant (2); or 10 to 90 parts, often 15 to 60 parts, more often 25 to 35 parts by weight of Reactant (3), or 10 to 90 parts by weight of reactant (4). The mixture, in the present invention, includes Reactant (3) and at least one other member of the group of reactants identified as reactants (1), (2) and (4). The sulfurization reaction generally is effected at an elevated temperature with agitation and optionally in an inert atmosphere and in the presence of an inert solvent. The sulfurizing agents useful in the process of the present invention include elemental sulfur, which is preferred, hydrogen sulfide, sulfur halide plus sodium sulfide, and a mixture of hydrogen sulfide and sulfur or sulfur dioxide. Typically often 0.5 to 3 moles of sulfur are employed per mole of olefinic bonds.

Amine salts of alkylphosphoric acids (xv) include salts of oleyl and other long chain esters of phosphoric acid, with amines as described below. Useful amines in this regard are tertiary-aliphatic primary amines, sold under the tradename Primene.™. The supplemental friction modifier can be used in addition to component (a). The amount of the supplemental friction modifier is generally 0.1 to 1.5 percent by weight of the lubricating composition, preferably 0.2 to 1.0 or 0.25 to 0.75 percent. In some embodiments, however, the amount of the supplemental friction modifier is present at less than 0.2 percent or less than 0.1 percent by weight, for example, 0.01 to 0.1 percent. In one embodiment the amount of dihydroxyethyl tallowamine (commercially sold as ENT-12.™.) in particular is restricted to these low amounts or less.

A wide variety of sulfur-containing extreme pressure or antiwear agents are available for use in the practice of this invention. Among suitable compositions for this use are included sulfurized animal or vegetable fats or oils, sulfurized animal or vegetable fatty acid esters, fully or partially esterified esters of trivalent or pentavalent acids of phosphorus, sulfurized olefins (see for example U.S. Pat. Nos. 2,995,569; 3,673,090; 3,703,504; 3,703,505; 3,796,661; 3,873,545; 4,119,549; 4,119,550; 4,147,640; 4,191,659; 4,240,958; 4,344,854; 4,472,306; and 4,711,736), dihydrocarbyl polysulfides (see for example U.S. Pat. Nos. 2,237,625; 2,237,627; 2,527,948; 2,695,316; 3,022,351; 3,308,166; 3,392,201; 4,564,709; and British 1,162,334), sulfurized Diels-Alder adducts (see for example U.S. Pat. Nos. 3,632,566; 3,498,915; and Re No. 27,331), sulfurized dicyclopentadiene (see for example U.S. Pat. Nos. 3,882,031 and 4,188,297), sulfurized or co-sulfurized mixtures of fatty acid esters and monounsaturated olefin (see for example U.S. Pat. Nos. 4,149,982; 4,166,796; 4,166,797; 4,321,153; 4,481,140), co-sulfurized blends of fatty acid, fatty acid ester and α-olefin (see for example U.S. Pat. No. 3,953,347), functionally-substituted dihydrocarbyl polysulfides (see for example U.S. Pat. No. 4,218,332), thia-aldehydes, thia-ketones and derivatives thereof (e.g., acids, esters, imines, or lactones) (see for example, U.S. Pat. No. 4,800,031; and International Application Publication No. WO 88/03552), epithio compounds (see for example, U.S. Pat. No. 4,217,233), sulfur-containing acetal derivatives (see for example U.S. Pat. No. 4,248,723), co-sulfurized blends of terpene and acyclic olefins (see for example U.S. Pat. No. 4,584,113), and polysulfide olefin products (see for example U.S. Pat. No. 4,795,576).

Preferred sulfur-containing extreme pressure or antiwear agents sulfur-containing organic compounds in which the sulfur-containing species are bound directly to carbon or to more sulfur.

A particularly preferred class of such agents is made by reacting an olefin, such as isobutene, with sulfur. The product, e.g., sulfurized isobutene, preferably sulfurized polyisobutylene, typically has a sulfur content of 10 to 55%, preferably 30 to 50% by weight. A wide variety of other olefins or unsaturated hydrocarbons, e.g., isobutene dimer or trimer, may be used to form such agents.

Another particularly preferred class of such agents is that of polysulfides composed of one or more compounds represented by the formula: R6-S_(x)—R7 where R6 and R7 are hydrocarbyl groups each of which preferably contains 3 to 18 carbon atoms and x is preferably in the range of from 2 to 8, and more preferably in the range of from 2 to 5, especially 3. The hydrocarbyl groups can be of widely varying types such as alkyl, cycloalkyl, alkenyl, aryl, or aralkyl. Tertiary alkyl polysulfides such as di-tert-butyl trisulfide, and mixtures comprising di-tert-butyl trisulfide (e.g., a mixture composed principally or entirely of the tri, tetra-, and pentasulfides) are preferred. Examples of other useful dihydrocarbyl polysulfides include the diamyl polysulfides, the dinonyl polysulfides, the didodecyl polysulfides, and the dibenzyl polysulfides.

The invention will be further illustrated by means of the following examples. The following examples illustrate the invention and are not to be used to limit the scope of the invention.

Preparation of Amine Tungstates from Tungstic Acid (Method A)

A mixture of the starting amine (2 eq.), tungstic acid (1 eq.), dissolved in aqueous ammonia was stirred at 95-1100 C for 2-3 hrs, and water and excess ammonia were then removed by distillation followed by the isolation of the product as viscous liquid.

Preparation of Amine Tungstates from Ammonium Para Tungstate (Method B)

A mixture of the starting amine (26 eq.) and aqueous ammonium paratungstate (1 eq.) was heated with vigorous mixing. Water and excess ammonia were then removed by distillation followed by the isolation of the product as viscous liquid.

Preparation of Amine Tungstates from Metal Tungstates (Method C)

Tungstic acid can also be prepared from an appropriate metal tungstate and sulfuric acid. The reaction of tungstic acid (1 eq.) with the appropriate amine (2 eq.) can be conducted in a hydrocarbon solvent at elevated temperatures, to yield the desired amine tungstate product.

Preparation of Amine Tungstates from Metal Tungstates and Quaternary Ammonium Halides or Sulfates (Method D)

The amine tungstates can also be prepared by the reaction of quaternary ammonium halides or sulfates, in heptane with sodium or potassium tungstate in water.

Method Physical Example Starting amine Used Form % W 1 Primene JMT(C₁₆-C₂₂ tert-alkyl primary A Yellow 18.7 aliphatic amine) Liquid 2 Primene JMT(C₁₆-C₂₂ tert-alkyl primary B Yellow 19.5 aliphatic amine) Liquid 3 Primene JMT(C₁₆-C₂₂ tert-alkyl primary C Yellow 11 aliphatic amine) Liquid 4 Primene JMT(C₁₆-C₂₂ tert-alkyl primary C Yellow 32.6 aliphatic amine) (tungstic Liquid acid:amine 1:1) 5 Primene JMT(C₁₆-C₂₂ tert-alkyl primary D Yellow 34 aliphatic amine) viscous Liquid 6 Primene 81R(C12-C14 tert-alkyl primary A White waxy 18 aliphatic amine amine) solid 7 Di(tridecyl) amine A Yellow 9.1 liquid 8 Di(tridecyl) amine B Yellow 15.0 liquid 9 Di(tridecyl) amine C Yellow 28.4 liquid 10 Salt of N-oleyl-1,3-propanediamine B Blue-Green 8.9 (Duomeen OL), with Dinonyl naphthalene Liquid sulfonic acid 11 Salt of N-oleyl-1,3-propanediamine B Blue-Green 8.3 (Duomeen OL), with Didodecyl naphthalene Liquid sulfonic acid 12 Salt of N-oleyl-1,3-propanediamine B Yellow 13.8 (Duomeen OL), with Naphthenic acid liquid 13 Reaction product of Canola Oil with N- B Yellow 9.6 oleyl-1,3-propanediamine (Duomeen OL) Liquid 14 Reaction product of aminoethyl imidazoline C Yellow 8.0 with Didodecyl naphthalene sulfonic acid Liquid 15 Bis succinimide from alkenyl succinic B Yellow 2.5 anhydride and diethylene triamine Liquid 16 Bis(2-hydroxyethyl)cocoalkylamine B Yellow 17.4 Liquid 17 Alkyl (C14-C18) bis(2-hydroxyethyl) B Yellow 5.7 amine Liquid 18 Alkyl (C14-C18) bis(2-hydroxyethyl) B Yellow 7.9 amine Liquid 19 Salt of N-oleyl-1,3- B Yellow 7.4 propanediamine(Duomeen OL), with Di(2- Liquid ethylhexyl) phosphonic acid 20 Salt of N-oleyl-1,3- B Brown 10.9 propanediamine(Duomeen OL), with Di(2- Liquid ethylhexyl) dithiophosphoric acid 21 Bis succinimide from alkenyl succinic C Yellow 8.3 anhydride and diethylene triamine Liquid 22 Salt of N-oleyl-1,3- B Yellow propanediamine(Duomeen OL), with Liquid dioleyl phosphonic acid

Preparation of New Amine Molybdates

A solution of starting amine (2 eq.), in heptane was combined with Molybdenum trioxide (1 eq.) in water and the resulting mixture was heated under reflux for 4-6 hrs. Water was removed by azeotropic distillation, under reduced pressure, resulting in the desired amine molybdates as a viscous oily product.

Another method involved the reaction of sodium molybdate (1 eq.) in water with amine (2 eq.) at 60-70° C., for 1 hr., followed by the addition of 1 eq., of aqueous sulfuric acid. The aqueous layer was separated and the organic residue was dehydrated under reduced pressure tresulting in the desired molybdate as a viscous oily product.

Yet another method involved the reaction of ammonium molybdate (1 eq.), with amine (2 eq.) in refluxing toluene, and removing water continuously. The molybdate was isolated as a viscous liquid.

Moly source Physical Example Starting amine Used Form % Mo 23 Salt of N-oleyl-1,3-propanediamine (Duomeen MoO₃ Brown 5.37 OL), with Dinonyl naphthalene sulfonic acid Liquid 24 Salt of N-oleyl-1,3-propanediamine (Duomeen MoO₃ Viscous 4.1 OL), with Naphthenic acid Yellow Liquid 25 Salt of N-oleyl-1,3-propanediamine(Duomeen MoO₃ Yellow 4.2 OL), with Di(2-ethylhexyl) phosphoric acid Liquid 26 Bis succinimide from alkenyl succinic MoO₃ Viscous 2.6 anhydride and diethylene triamine Green Liquid 27 Salt of N-oleyl-1,3-propanediamine(Duomeen MoO₃ Brown 6.3 OL), with Di(2-ethylhexyl) dithiophosphoric Liquid acid

Test for Oxidation Induction Time by Pressure Differential Scanning Calorimetry (PDSC)

The Pressure Differential Scanning Calorimetry (PDSC) test method is a thin film high temperature catalytic oxidation test, for determination of oxidation induction time (OIT). The procedure used for this analysis was ASTM 6186-03. In the test, the compounds to be evaluated for antioxidancy performance were added at the required treat rate to a sample of Chevron Group II ISOVG 46 base oil containing no other additive. This test sample (6-9 mg) was placed in the center of an aluminum DSC pan and inserted into a DuPont 910 High Pressure DSC, equipped with a pressure cell and interfaced to a TA Instruments 2000 thermal analysis controller. The pressure cell of the DSC was closed, purged with O₂, equilibrated at 70° C., and heated to 210° C. at a rate of 40° C./min. When the temperature had reached 209° C. the cell was pressurized with oxygen to a pressure of 500 psi and the cell held at 210° C. After a period of time the test sample underwent an exothermic oxidative reaction; this event and magnitude of the associated heat effects compared to the inert reference were monitored and recorded. The data obtained was analyzed using TA Instruments Universal Analysis program V4.1D. The oxidation induction time (OIT; time to auto-oxidation) is the time at which the baseline intersects with a line tangent to the curve of the exothermal heat flow versus time scan. The OIT is reported in minutes. The magnitude of the OIT is an indication of the effectiveness of the compounds or compound mixtures under test as antioxidants; the larger the OIT the greater the antioxidant effect.

Oxidation induction time Sample (minutes) 0.5% amine tungstate of Ex. 1 0 0.5% NA-LUBE AO142(Octyl/butyldiphenyl amine) 2.8 0.5% NA-LUBE AO142(Octyl/butyldiphenyl amine) + 12.0 900 ppm amine tungstate of Ex. 1 Clearly the amine tungstates of the current invention provided synergistic antioxidant activity, in combination with aminic antioxidants. Synergistic antioxidant effects of combining amine tungstate compounds of the current invention with an aminic antioxidant were noted with a larger OIT for these combinations.

Oxidative Stability by Rotating Pressure Vessell Oxidation Test (RPVOT)

Also thermo-oxidative stability of these synergistic mixtures in combination with Group II base oil at various concentrations were determined using the ASTM D 2272 Rotating Pressure Vessell Oxidation Test (RPVOT) method.

The RPVOT test utilizes an oxygen-pressure bomb to evaluate the oxidation stability of oils in the presence of water and a copper catalyst coil at 150° C. The test oil, water and a copper catalyst coil, contained in a covered glass container, were placed in a vessel equipped with a pressure gauge. The bomb was charged with oxygen to a pressure of 90 psi, placed in a constant temperature oil bath at 150° C., and rotated axially at 100 rpm at an angle of 30° from the horizontal. The time period required for the pressure to drop to 25 psi is the measure of the oxidation stability of the test sample: the longer the time, the better the oxidative stability of the material.

Sample in Chevron ISO VG 46 base Oil W (ppm) RPVOT minutes No additive 38 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) — 313 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 142 1359 amine tungstate of Ex. 10 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 133 1274 amine tungstate of Ex. 11 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 139 918 amine tungstate of Ex. 16 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 143 1202 amine tungstate of Ex. 17 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 145 1163 amine tungstate of Ex. 15 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 142 1170 amine tungstate of Ex. 18 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 142 828 amine tungstate of Ex. 8 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 142 532 amine tungstate of Ex. 9 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl amine) + 142 801 amine tungstate of Ex. 5 0.5% NA-LUBE AO142(Octyl/butyldiphenyl amine) + 140 1023 amine tungstate of Ex. 12 0.5% NA-LUBE AO142(Octyl/butyldiphenyl amine) + 140 1790 amine tungstate of Ex. 14 0.5% NA-LUBE AO142(Octyl/butyldiphenyl amine) + 140 636 amine tungstate of Ex. 13

Synergistic antioxidant effects of combining amine tungstate compounds of the current invention with an aminic antioxidant were once again noted with a larger induction time for these combinations.

RPVOT Sample in Chevron ISO VG 46 base Oil W (ppm) minutes No additive 38 Amine tungstate of Ex. 1 144 32 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl — 313 amine) 0.5% NA-LUBE ® AO142(Octyl/butyldiphenyl 144 865 amine) + amine tungstate of Ex. 1 0.7% ZDDP(Zinc dialkyldithiophosphate) — 130 0.7% ZDDP(Zinc dialkyldithiophosphate) + 144 488 amine tungstate of Ex. 1

Synergistic antioxidant effects of combining amine tungstate compounds of the current invention with an aminic antioxidant, and a dialkyl dithiophosphate were once again noted with a larger induction time for these combinations.

Friction Performance

The friction coefficients of compounds of current invention were evaluated in prototype motor oil using a modified ASTM D5707 SRV Ball on Plate protocol; 400N, 50 Hz; 1.00 mm stroke 120° C.; 120 min. The data showed an improvement in friction coefficient for compounds of current invention compared to the base oil with no friction modifier additive.

Sample in Chevron ISO VG 46 base Oil, containing ashless dithiophosphate, ZDDP, Final friction triphenylphosphate ester, and alkylated coefficient) naphthalene sulfonate rust inhibitor W (ppm) after 120 min.) No additive — 0.103 Ex. 8 142 0.069 Ex. 5 142 0.065 Ex. 9 142 0.085 Ex. 1 144 0.061 Ex. 2 142 0.062 Ex. 10 142 0.076 Ex. 18 142 0.070 Ex. 11 142 0.079 Ex. 12 142 0.079 Ex. 13 451 0.071 Ex. 14 448 0.078 Ex. 17 143 0.080 Ex. 19 500 0.061 Sample in Exxon Superflo 10w-30 Final friction coefficient) oil Mo (ppm) after 120 min.) No additive — 0.135 Molyvan 855 800 0.054 Ex. 23 537 0.053 Ex. 24 520 0.057 Ex. 25 521 0.063 Ex. 26 520 0.054

I. Synergy of Amine Tungstates with Metal-Containing Antiwear Additives

a) Oxidative Stability by Rotating Pressure Vessel Oxidation Test

The synergistic thermo-oxidative stability of combinations of the amine tungstates of the invention and metal-containing antiwear additives in an ISO VG 46 Group II oil containing an amine antioxidant is demonstrated using the ASTM D 2272 Rotating Pressure Vessel Oxidation Test (RPVOT) method.

The RPVOT test utilizes an oxygen-pressure bomb to evaluate the oxidation stability of oils in the presence of water and a copper catalyst coil at 150° C. The test oil, water and a copper catalyst coil, contained in a covered glass container, were placed in a vessel equipped with a pressure gauge. The bomb was charged with oxygen to a pressure of 90 psi, placed in a constant temperature oil bath at 150° C. and rotated axially at 100 rpm at an angle of 30° from the horizontal. The time period (in minutes) required for the pressure to drop to 25 psi is the measure of the oxidation stability of the test sample: the longer the time, the better the oxidative stability of the material.

EXAMPLE 28

NALUBE AO-142, an alkylated diphenylamine antioxidant available from King Industries, Inc., Norwalk, Conn., the product of Example 2 and an ISO VG 46 Group II base oil from Chevron were blended in the amounts shown in Table 1 for 30 minutes at 50° C. The resulting formulated oil was evaluated for oxidative stability by the ASTM D 2272 Rotating Pressure Vessel Oxidation Test (RPVOT) as described above.

EXAMPLES 29-30

The formulated oils of Examples 29 and 30 were prepared using the procedure of Example 28 except that Molyvan 822, a molybdenum dialkyldithiocarbamate available from R. T. Vanderbilt was substituted completely or partially for the product of Example 2 in the amounts designated in Table 1.

The RPVOT results show that the formulation of Example 30, containing a combination of the amine tungstate and organomolybdenum compound (Molyvan 855) gave an improved oxidation stability compared to formulations containing only the amine tungstate or organomolybdate at equivalent total metal content.

TABLE 1 Example Components, wt % 28 29 30 NA-LUBE AO-142 0.25 0.25 0.25 Molyvan 822 (4.9% Mo) — 0.59 0.295 Amine Tungstate of Example 2 (18% W) 0.16 — 0.08 Chevron ISO 46 Grp II Base Oil 99.59 99.16 99.38 Molybdenum Content (ppm) 288 0 144 Tungsten Content (ppm) 0 288 144 Total Metal Content (ppm) 288 288 288

b) Wear Performance by ASTM D 4172 Four Ball Wear Testing

The synergistic wear performance of combinations of the amine tungstates of the invention and metal-containing antiwear additives in a formulated ISO VG Group II oil containing both and amine antioxidant and a phenolic antioxidant is demonstrated using the Four Ball Wear Test. The wear tests were conducted on a four ball friction and wear machine manufactured by Falex Corporation using the conditions specified in ASTM D 4172 test method. Tests were conducted at a temperature of 75° C., load of 40 Kg, rotation speed of 1200 rpm and test duration of 1 hour.

EXAMPLE 31

The base model formulated oil used for this test is shown in Table 1 to which a fixed amount of metal-containing antiwear additive was added. Metal-containing antiwear additives evaluated were Molyvan 822, a molybdenum dialkyldithiocarbamate available from R. T. Vanderbilt; Molyvan L, a molybdenum dialkylthiophosphate available from R. T. Vanderbilt; and Rhein Chemie RC 8210, a zinc dialkyldithiophosphate available from Rhein Chemie. To the formulation containing the fixed concentration of metal-containing antiwear additive was added increasing amounts of the amine tungstates of the invention (Example 2). Each resulting formulation was tested by the ASTM D 4172 Four Ball Wear Test. In all cases, the wear scar of formulations with the metal-containing antiwear additive decreased with increasing concentration of the amine tungstate of the invention (Example 2). It was also demonstrated that the amine tungstate at the highest concentration of Table 3 (0.32 wt percent) did not provide any improvement in wear scar over the base formulation of Table 2.

The results show that the amine tungstates of the invention impart little to no wear performance to formulated oils when used alone, however; the amine tungstates of the invention improve the wear performance of formulations already containing metal-containing antiwear additives as demonstrated by the improvement in wear performance with increasing amine tungstate concentration at a fixed concentration of the metal-containing antiwear additive.

TABLE 2 Base Formulation ASTM D 4172 Four-ball Wear Tests Additive Percent of Composition NA-LUBE AO-130 0.1 NA-LUBE AO-210 0.1 K-CORR NF-200 0.05 ISO VG 46 Gr II balance

TABLE 3 Amount of Amine Tungstate (Example 2) added to formulations containing the Metal-Containing Antiwear Additives at a Fixed Concentration Concentration of Amine Tungsten Tungstate, (Percent) Concentration (ppm) 0.04 72 0.08 144 0.16 288 0.32 576 a) Available from R. T. Vanderbilt as Molyvan 822 b) Available from R. T. Vanderbilt as Molybvan L c) Available from Rein Chemie as RC 3180.

II. Synergy of Amine Tungstates with Ashless Friction Modifiers

a) Anti-Friction Performance

The synergistic anti-friction performance of the amine tungstates of the invention in combination with ashless friction modifiers in a model formulated oil is demonstrated using an SRV4 friction and wear instrument manufactured by Optimol Instruments. The specific conditions for the all tests were according to ASTM D 5707 test method. All tests were conducted at 120° C. using a ball on plate configuration, a load of 400N, frequency of 50 Hz, a stroke of 1.00 mm stroke and test duration of 120 minutes. The coefficient of friction is measured as a function of time and an average coefficient of friction is calculated for the entire run at the completion of the test. A lower value for the average coefficient of friction is indicative of an oil with better anti-friction performance.

EXAMPLE 32

The amine tungstate of Example 2 and a bis(succinimide) ashless friction modifier derived from the reaction of C20-C24 alkenyl succinic anyhdride (available as ASA2024 from Dixie Chemical Company) and tetratethylenepentamine (available from Akzo Nobel Functional Chemicals, AB) are blended at 50° C. for 30 minutes with CP Chem PAO 40, CP Chem PAO 8, NALUBE KR-015, K-CORR NF 200, and a zinc dialkyldithiophosphate (RC 8210, available from Rhein Chemie) at the weight percentage composition according Table 4, Example 32. The formulated gear oil thus prepared contains 0.5 wt % of the amine tungstate and 0.5 wt % of the bis(succinimide) ashless friction modifier. The formulated oil is evaluated in the SRV friction and wear test according to the ASTM D 5707 general method using the specific conditions outlined above. The average coefficient of friction for the test was 0.044.

EXAMPLES 33-34

Formulated gear oils were prepared and tested according to the procedure of Example 32 using the amounts of each component listed in Table 4. The average coefficient of friction for Examples 33 and 34 were 0.083 and 0.10, respectively. The results of Examples 32-34 demonstrate that the anti-friction performance for the combination of the amine tungstate with a succinimide ashless friction modifier is significantly improved over the anti-friction performance of the amine tungstate and ashless friction modifier alone at equivalent total concentration.

EXAMPLES 35-37

Formulated gear oils were prepared and tested according to the procedure of Example 32 using the amounts of each component listed in Table 4. The average coefficient of friction for Examples 35-39 were 0.058, 0.10 and 0.105, respectively. The results of Examples 35-37 demonstrate that the anti-friction performance for the combination of the amine tungstate with a succinimide ashless friction modifier is significantly improved over the anti-friction performance of the amine tungstate and ashless friction modifier alone at equivalent total concentration.

EXAMPLES 38-39

Formulated gear oils were prepared and tested according to the procedure of Example 32 using the amounts of each component listed in Table 4. In this case the succinimide ashless friction modifier was replaced with glycerol monooleate. The average coefficient of friction for Examples 38 (containing the combination of amine tungstate of Example 2 and glycerol monooleate) was significantly lower than that of Example 33 (containing only the amine tungstate of Example 2) and Example 39 (containing only glycerol monooleate). The results of Examples 33, 38 and 39 demonstrate that the anti-friction performance for the combination of the amine tungstate with an ashless glycerol ester friction modifier is significantly improved over the anti-friction performance of the amine tungstate and ashless friction modifier alone at equivalent total concentration.

EXAMPLES 40-41

Formulated gear oils were prepared and tested according to the procedure of Example 32 using the amounts of each component listed in Table 4. In this case the succinimide ashless friction modifier was replaced with cocoamide diethanolamine ashless friction modifier. The results of Examples 33, 40 and 41 demonstrate that the anti-friction performance for the combination of the amine tungstate with an ashless hydroxyalkylamide friction modifier is significantly improved over the anti-friction performance of the amine tungstate and ashless friction modifier alone at equivalent total concentration.

TABLE 4 Example 32 33 34 35 36 37 38 39 40 41 Components PAO 40^(a) 70.10 70.10 70.10 70.60 70.6 70.6 70.10 70.10 70.10 70.10 PAO 8^(b) 17.78 17.78 17.78 17.78 17.78 17.78 17.78 17.78 17.78 17.78 Alkylated Aromatic^(c) 9.87 9.87 9.87 9.87 9.87 9.87 9.87 9.87 9.87 9.87 Zinc 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Dialkyldithiophosphate Benzotriazole derivative 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 yellow metal deactivator^(e) Amine Tungstate of 0.50 1.0 0 0.25 0.50 0 0.50 0 0.50 0 Example 2 Bis(succinimide) Ashless 0.50 0 1.0 0.25 0 0.50 — — — — Friction Modifier Glycerol Monooleate — — — — — — 0.50 1.0 — — Ashless Friction Modifier Cocamide DEA Ashless — — — — — — — — 0.50 1.0 Friction Modifier^(f) Average Coefficient of 0.044 0.083 0.10 0.058 0.10 0.105 Friction ^(a)Available from CP Chem ^(b)Available from CP Chem ^(c)KR-015 from King Industries, Inc. ^(d)RC-8210 from Rhein Chemie ^(e)K-CORR NF 200 from King Industries, Inc. ^(f)AMIDEX DEA from Noveon/Lubrizol

III. Synergy of Amine Tungstates with Ash Less Antiwear Additives

EXAMPLE 42

The amine tungstate of Example 2 is blended at 50° C. for 30 minutes with an ISO VG 46 Group II base oil, a nonylated diphenylamine antioxidant (NA-LUBE AO-130), a phenolic antioxidant (NALUBE AO-210, and a triazole yellow metal deactivator (K-CORR NF 200) at the weight percentage composition according Table 5, Example 42. The formulated oil thus prepared contains 0.32 wt % of the amine tungstate of Example 2 and 576 ppm of tungsten. The oil was evaluated by the ASTM D 4172 Four Ball Wear Test and gave a wear scar of 0.80 mm.

EXAMPLE 43

The procedure of Example 42 was repeated except that the amine tungstate of Example 2 component was omitted. The resulting wear scar was 0.78.

The results of Examples 42 and 43 demonstrate that the amine tungstates of the invention do not provide antiwear performance when used alone.

EXAMPLES 44-47

The procedure of Example 42 was repeated for Examples 44-47 using the amounts of each component specified in Table 5. Each of these examples contained 0.25 percent of an ashless dialkyldithiocarbamate antiwear additive (NALUBE ADTC, available from King Industries, Inc.). The wear scar for each formulation is reported in Table 5. The results demonstrate the synergistic performance derived from the combination of the amine tungstates of the invention with ashless antiwear additives in that the wear performance of the formulation improves with increasing concentration of tungsten in the presence of a constant concentration of ashless antiwear additive.

TABLE 5 Example 42 43 44 45 46 47 48 Composition (%) NA-LUBE AO-130 0.1 0.1 0.1 0.1 0.1 0.1 0.1 NA-LUBE AO-210 0.1 0.1 0.1 0.1 0.1 0.1 0.1 K-CORR NF-200 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Amine Tungstate of 0.32 — 0 0.04 0.08 0.16 0.32 Example 2 Ashless — — 0.25 0.25 0.25 0.25 0.25 dialkyldithiocarbamate (NALUBE ADTC) ISO VG 46 Group II balance balance balance balance balance balance balance base oil Tungsten 576 0 0 72 144 288 576 Concentration (ppm) ASTM D 2172 Wear 0.80 0.78 0.72 0.72 0.65 0.58 0.50 Scar (mm) *All NALUBE ™ products are available from King Industries, Inc.

IV. Synergy of Amine Tungstates with Extreme Pressure Additives

It has been demonstrated that the addition of amine tungstates to lubricant formulations containing extreme pressure additives results in improved performance in the ASTM D 2783 Four Ball Weld Test. The Four Ball Extreme Pressure Test measures a lubricant's extreme pressure properties under high Hertzian contact under pure sliding, or pure rolling, motion. In the test, a ½ inch steel ball is rotated while under load contact with 3 similar steel balls held stationary in test cup while immersed in the test lubricant. A timed test is performed. The test is repeated with new steel balls and test lubricant under increasing load increments until the top rotating ball welds to the lower stationary balls. The point at which the balls weld together is the “weld load”. A higher weld load is associated with a lubricant with better extreme pressure performance.

EXAMPLE 49

A semi-synthetic gear oil formulation was prepared by blending the amine tungstate of Example 2 with a ISO VG 46 base oil, a synthetic ester (Emery 2970), a viscosity index improver (Viscoplex 0-030) for 30 minutes at 50° C. in the amounts reported in Table 6. This formulation contains HiTEC 350, a commercial automotive and industrial gear oil additive package from Afton Chemical. HiTEC 350 is a blend of various antioxidants, antiwear additives such as alkyl phosphates and extreme pressure additives such as sulfurized olefins and esters. The major constituents of the package are sulfurized hydrocarbon extreme pressure additives. When used at a treat level of 5.25 wt %, HiTEC 350 delivers 1.6% of sulfur to the final formulated oil. Formulations prepared using HiTEC 350 at 5.25 wt % in suitable base stocks meet the performance requirements of API GL-5 and MIL-L-2105D specifications for automotive gear lubricants. The formulated gear oil thus prepared was evaluated in the ASTM D 2783 test. The weld load is reported in Table 6.

EXAMPLE 50

The procedure of Example 49 was repeated except that the amine tungstate of Example 2 was omitted from the formulation.

TABLE 6 Example Composition (all values in percent) 49 50 Amine Tungstate of Example 2 0 0.36 Rohm and Haas Viscoplex 0-030 VI Improver 20 20 Emery 2970 Synthetic Ester 9.75 9.75 HiTEC 350 Gear Oil Package 5.25 5.25 Chevron 220 R ISO VG 46 Tungsten Content of Formulation 700 0 Weld Load (Kg) 260 240

The results of the four ball extreme pressure tests demonstrate the improved performance of the formulations containing a combination of the amine tungstates of the invention with extreme pressure additives. 

1. A lubricating oil composition providing improved performance properties, comprising: 1) a lubricating oil; 2) at least one oil-soluble or oil-dispersible organo amine tungstate; and 3) an oil-soluble secondary diaryl amine and/or an oil-soluble alkylated phenothiazine; 4) an ashless friction modifier, a metal-containing antiwear additive, an ashless antiwear additive, an extreme pressure agent, a corrosion inhibitor/detergent, a yellow metal deactivator/copper passivating agent, a pour point depressant or mixtures thereof, and optionally one or more antioxidant, dispersant, detergent, friction modifier, antiwear additive, corrosion inhibitor, metal deactivator, fuel economy agent, viscosity index improver, or mixtures thereof.
 2. The lubricating oil composition of claim 1, wherein said composition has a performance property that is better than the same performance property of both a) an analogous composition without 2); and b) an analogous composition without 4).
 3. The lubricating oil composition of claim 2, wherein said performance property is oxidative stability.
 4. The lubricating oil composition of claim 2, wherein said performance property is anti-friction performance. 